Name: ProxySG

Text: Blue Coat® Systems
ProxySG® Appliance

Configuration and Management Suite
Volume 2: Proxies and Proxy Services

Version SGOS 5.3.x

Volume 2: Proxies and Proxy Services

Contact Information
Blue Coat Systems Inc.
420 North Mary Ave
Sunnyvale, CA 94085-4121
http://www.bluecoat.com/support/contactsupport
http://www.bluecoat.com
For concerns or feedback about the documentation: [email protected]

Copyright© 1999-2008 Blue Coat Systems, Inc. All rights reserved worldwide. No part of this document may be reproduced by any means
nor modified, decompiled, disassembled, published or distributed, in whole or in part, or translated to any electronic medium or other
means without the written consent of Blue Coat Systems, Inc. All right, title and interest in and to the Software and documentation are
and shall remain the exclusive property of Blue Coat Systems, Inc. and its licensors. ProxyAV™, CacheOS™, SGOS™, SG™, Spyware
Interceptor™, Scope™, ProxyRA Connector™, ProxyRA Manager™, Remote Access™ and MACH5™ are trademarks of Blue Coat
Systems, Inc. and CacheFlow®, Blue Coat®, Accelerating The Internet®, ProxySG®, WinProxy®, AccessNow®, Ositis®, Powering
Internet Management®, The Ultimate Internet Sharing Solution®, Cerberian®, Permeo®, Permeo Technologies, Inc.®, and the Cerberian
and Permeo logos are registered trademarks of Blue Coat Systems, Inc. All other trademarks contained in this document and in the
Software are the property of their respective owners.
BLUE COAT SYSTEMS, INC. DISCLAIMS ALL WARRANTIES, CONDITIONS OR OTHER TERMS, EXPRESS OR IMPLIED,
STATUTORY OR OTHERWISE, ON SOFTWARE AND DOCUMENTATION FURNISHED HEREUNDER INCLUDING WITHOUT
LIMITATION THE WARRANTIES OF DESIGN, MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL BLUE COAT SYSTEMS, INC., ITS SUPPLIERS OR ITS LICENSORS BE LIABLE FOR
ANY DAMAGES, WHETHER ARISING IN TORT, CONTRACT OR ANY OTHER LEGAL THEORY EVEN IF BLUE COAT SYSTEMS,
INC. HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

Document Number: 231-03011
Document Revision: SGOS 5.3.1—08/2008

ii

Contents
Contact Information

Chapter 1: Introduction

About This Book................................................................................................................................ 11
Document Conventions ................................................................................................................... 11
Notes and Warnings ......................................................................................................................... 12
About Procedures ............................................................................................................................. 12
Illustrations ........................................................................................................................................ 12
....................................................................................................................................................... 13
Chapter 2: About Management Services

Overview of Management Services................................................................................................ 15
Creating a Management Service ..................................................................................................... 16
Managing the HTTP Console .......................................................................................................... 18
Managing the HTTPS Console (Secure Console) ......................................................................... 18
Selecting a Keyring..................................................................................................................... 18
Selecting an IP Address ............................................................................................................. 19
Enabling the HTTPS Console Service...................................................................................... 19
Managing the SNMP Console ......................................................................................................... 20
Managing the SSH Console ............................................................................................................. 20
Managing the SSH Host ............................................................................................................ 21
Managing SSH Client Keys....................................................................................................... 22
Managing the Telnet Console ......................................................................................................... 24
Chapter 3: About Proxy Services and Proxies

About Proxy Listeners ............................................................................................................... 28
About Service Attributes and Proxy Services ........................................................................ 29
About Multiple Listeners .......................................................................................................... 30
About Proxy Service Groups .................................................................................................... 31
About Protocol Detection .......................................................................................................... 32
Section A: Managing Proxy Services and Service Groups

Viewing Proxy Services.................................................................................................................... 34
Changing Listener Actions for a Service Group........................................................................... 34
Moving a Service Among Groups .................................................................................................. 35
Deleting a Service or Service Group............................................................................................... 35
Section B: Creating or Editing a Proxy Service

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Volume 2: Proxies and Proxy Services

Creating a New Proxy Service ........................................................................................................ 37
Editing an Existing Proxy Service .................................................................................................. 39
Importing a Service from the Service Library .............................................................................. 40
Section C: About Global Options for Proxy Services

Reflecting the Client Source IP when Connecting to Servers..................................................... 43
Trusting the Destination IP Address Provided by the Client .................................................... 43
Enabling the ProxySG to Trust the Client-Provided Destination IP Address................... 44
Tip................................................................................................................................................. 44
Managing User Limits...................................................................................................................... 44
Determining Behavior if User Limits are Exceeded.............................................................. 45
Setting User Limits Notifications............................................................................................. 46
Viewing Concurrent Users ....................................................................................................... 47
Configuring General Options ......................................................................................................... 47
Section D: About the Bypass List

Adding Static Bypass Entries .......................................................................................................... 49
Using Policy to Configure Dynamic Bypass................................................................................. 50
Notes ............................................................................................................................................ 50
Configuring Dynamic Bypass .................................................................................................. 51
Section E: Using Restricted Intercept
Section F: Proxy Services and Listeners

Reference: Access Log Fields .......................................................................................................... 57
Reference: VPM Objects................................................................................................................... 58
Reference: CPL Policy Configuration for Service Group............................................................ 58
Chapter 4: Accelerating File Sharing

About the CIFS Protocol .................................................................................................................. 59
About the Blue Coat CIFS Proxy Solution .................................................................................... 60
Caching Behavior ....................................................................................................................... 61
Authentication ............................................................................................................................ 61
Policy Support ............................................................................................................................ 61
Access Logging........................................................................................................................... 61
WCCP Support ........................................................................................................................... 61
Configuring the ProxySG CIFS Proxy ........................................................................................... 62
About Windows Security Signatures ...................................................................................... 62
Intercepting CIFS Services ........................................................................................................ 63
Adding and Configuring New CIFS Services........................................................................ 64
Configuring the CIFS Proxy Options ...................................................................................... 67
Enabling CIFS Access Logging ................................................................................................ 69
Reviewing CIFS Protocol Statistics.......................................................................................... 69
Reference: Equivalent CIFS Proxy CLI Commands .................................................................... 72

iv

Contents

Reference: Access Log Fields .......................................................................................................... 73
Reference: CPL Triggers, Properties, and Actions....................................................................... 76
Triggers........................................................................................................................................ 76
Properties and Actions: ............................................................................................................. 76
Chapter 5: Managing the Domain Name Service (DNS) Proxy

Configuring the DNS Proxy Service Options ............................................................................... 79
Changing the Default DNS Proxy Service to Intercept All IP Addresses on Port 53....... 79
Creating or Editing a DNS Proxy Service ..................................................................................... 80
Creating a Resolving Name List..................................................................................................... 82
Chapter 6: Accelerating the Microsoft Outlook Application (Endpoint Mapper and MAPI Proxies)
Section A: The Endpoint Mapper Proxy Service

About RPC ......................................................................................................................................... 84
About the Blue Coat Endpoint Mapper Proxy Solution ............................................................. 84
Policy Support ............................................................................................................................ 85
Access Logging........................................................................................................................... 85
Configuring Endpoint Mapper Service Options.......................................................................... 85
Configuring the Endpoint Mapper Service to Intercept All IP Addresses on Port 135... 85
Adding a New Endpoint Mapper Service .............................................................................. 86
Reviewing Endpoint Mapper Proxy Statistics.............................................................................. 89
Reference: Equivalent Endpoint Mapper Proxy CLI Commands ............................................. 90
Reference: Access Log Fields .......................................................................................................... 90
Reference: CPL Triggers, Properties, and Actions....................................................................... 91
TCP Tunneling Triggers............................................................................................................ 91
Properties and Actions .............................................................................................................. 92
Section B: The MAPI Proxy

About MAPI ...................................................................................................................................... 93
About the Blue Coat MAPI Solution.............................................................................................. 93
Reducing RPC Messages Across the WAN............................................................................ 94
Maintaining Exchange Connections........................................................................................ 95
Supported Servers...................................................................................................................... 95
Access Logging........................................................................................................................... 95
More Conceptual Reference ..................................................................................................... 95
Configuring the ProxySG MAPI Proxy ......................................................................................... 95
About the MAPI Service ........................................................................................................... 96
Configuring the MAPI Proxy ................................................................................................... 96
Reviewing MAPI Statistics .............................................................................................................. 97
Reference: Equivalent MAPI Proxy CLI Commands .................................................................. 97
Reference: Access Log Fields .......................................................................................................... 98

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Volume 2: Proxies and Proxy Services

Chapter 7: Managing the File Transport Protocol (FTP) Proxy

How Do I...? ..................................................................................................................................... 101
About FTP........................................................................................................................................ 102
Terminology.............................................................................................................................. 102
Configuring IP Addresses for FTP Control and Data Connections.................................. 102
Configuring the ProxySG for Native FTP Proxy........................................................................ 104
Changing the Default FTP Proxy Service to Intercept........................................................ 105
Creating or Editing the FTP Service ...................................................................................... 105
Configuring the FTP Proxy..................................................................................................... 107
Configuring FTP Clients ......................................................................................................... 108
Configuring FTP Connection Welcome Banners ....................................................................... 109
Viewing FTP Statistics.................................................................................................................... 110
Chapter 8: Intercepting and Optimizing HTTP Traffic

How Do I...? ..................................................................................................................................... 111
Section A: About the HTTP Proxy Service

Configuring the HTTP Proxy Service Options........................................................................... 113
Changing the HTTP Proxy Service to Intercept All IP Addresses on Port 80................. 113
Creating or Editing an HTTP Proxy Service............................................................................... 114
Configuring IE for Web FTP with an Explicit HTTP Proxy............................................... 118
Section B: Configuring the HTTP Proxy Performance

Customizing the HTTP Object Caching Policy .......................................................................... 119
About Object Pipelining.......................................................................................................... 120
About HTTP Object Types...................................................................................................... 121
About Meta Tags ...................................................................................................................... 122
About Tolerant HTTP Request Parsing ................................................................................ 122
Configuring the Global Defaults on the HTTP Object Caching Policy ............................ 123
Selecting an HTTP Proxy Acceleration Profile........................................................................... 127
Using the Normal Profile ........................................................................................................ 128
Using the Portal Profile ........................................................................................................... 128
Using the Bandwidth Gain Profile ........................................................................................ 128
About HTTP Proxy Profile Configuration Components .......................................................... 129
Configuring the HTTP Proxy Profile .................................................................................... 133
Fine-Tuning Bandwidth Gain ....................................................................................................... 135
Allocating Bandwidth to Refresh Objects in Cache ............................................................ 135
Using Byte-Range Support ..................................................................................................... 136
Enabling Revalidate Pragma-No-Cache ............................................................................... 138
Interpreting Negative Bandwidth Gain Statistics...................................................................... 138
Section C: Caching Authenticated Data (CAD) and Caching Proxy Authenticated Data (CPAD)

About Caching Authenticated Data (CAD) ......................................................................... 141

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Contents

About Caching Proxy Authenticated Data (CPAD) ........................................................... 142
Section D: Viewing HTTP/FTP Statistics

HTTP/FTP History Statistics ................................................................................................. 145
Section E: Supporting IWA Authentication in an Explicit HTTP Proxy

Disabling the Proxy-Support Header.................................................................................... 149
Chapter 9: Configuing and Managing an HTTPS Reverse Proxy Service
Section A: Configuring the HTTPS Reverse Proxy

Changing the HTTPS Proxy Service to Intercept All IP Addresses on Port 443............. 152
Creating an HTTPS Reverse Proxy Service .......................................................................... 152
Section B: Configuring HTTP or HTTPS Origination to the Origin Content Server

Creating Policy for HTTP and HTTPS Origination ................................................................... 158
Chapter 10: Managing Shell Proxies

About Shell Proxies ........................................................................................................................ 159
Customizing Policy Settings for Shell Proxies............................................................................ 160
Conditions ................................................................................................................................. 160
Properties .................................................................................................................................. 160
Actions ....................................................................................................................................... 161
Boundary Conditions for Shell Proxies................................................................................. 161
About Telnet Shell Proxies ............................................................................................................ 161
Configuring the Telnet Shell Proxy Service Options................................................................. 162
Changing the Telnet Shell Proxy Service to Intercept All IP Addresses on Port 23....... 162
Creating or a New Telnet Shell Proxy Service............................................................................ 163
Viewing Shell History Statistics.................................................................................................... 166
Chapter 11: Managing a SOCKS Proxy

Configuring the SOCKS Proxy Service Options ........................................................................ 168
Changing the SOCKS Proxy Service to Intercept All IP Addresses on Port 1080 .......... 168
Creating or Editing a SOCKS Proxy Service............................................................................... 168
Configuring the SOCKS Proxy ..................................................................................................... 170
Using Policy to Control the SOCKS Proxy.................................................................................. 171
Using the Permeo PA SOCKS Client with the Blue Coat SOCKS Server............................... 172
Viewing SOCKS History Statistics ............................................................................................... 174
Viewing SOCKS Clients .......................................................................................................... 174
Viewing SOCKS Connections ................................................................................................ 175
Viewing SOCKS Client and Server Compression Gain Statistics .................................... 175
Chapter 12: Managing the SSL Proxy

Understanding the SSL Proxy....................................................................................................... 177
Validating the Server Certificate............................................................................................ 178

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Volume 2: Proxies and Proxy Services

Determining What HTTPS Traffic to Intercept.................................................................... 178
Managing Decrypted Traffic .................................................................................................. 179
Using the SSL Proxy with ADN Optimization........................................................................... 179
Section A: Intercepting HTTPS Traffic

Setting Up the SSL Proxy in Transparent Proxy Mode............................................................. 182
Setting Up the SSL Proxy in Explicit Proxy Mode ..................................................................... 184
Specifying an Issuer Keyring and CCL Lists for SSL Interception ................................... 185
Using Client Consent Certificates.......................................................................................... 186
Downloading an Issuer Certificate ........................................................................................ 186
Section B: Configuring SSL Rules through Policy

Using the SSL Intercept Layer ...................................................................................................... 190
Using the SSL Access Layer .......................................................................................................... 192
CPL in the SSL Intercept Layer..................................................................................................... 194
CPL in the SSL Layer...................................................................................................................... 195
Notes................................................................................................................................................. 196
Section C: Viewing SSL Statistics

SSL History Statistics...................................................................................................................... 197
Unintercepted SSL Data .......................................................................................................... 197
Unintercepted SSL Clients ...................................................................................................... 198
Unintercepted SSL Bytes ......................................................................................................... 198
Section D: Advanced Topics

Creating an Intermediate CA using OpenSSL............................................................................ 200
Installing OpenSSL .................................................................................................................. 200
Creating a Root Certificate...................................................................................................... 200
Modifying the OpenSSL.cnf File ............................................................................................ 201
Signing the ProxySG CSR ....................................................................................................... 202
Importing the Certificate into the ProxySG.......................................................................... 202
Creating an Intermediate CA using Microsoft Server 2003 (Active Directory)..................... 203
Chapter 13: Managing the TCP Tunneling Proxy

TCP-Tunnel Proxy Services Supported ....................................................................................... 207
Configuring the TCP-Tunnel Proxy Service Options................................................................ 208
Changing the TCP-Tunnel Proxy Service to Intercept All IP Addresses on All Unattended
Ports ..................................................................................................................................... 208
Creating or Editing a TCP-Tunnel Proxy Service ...................................................................... 208
Appendix A: Explicit and Transparent Proxy

About the Explicit Proxy ............................................................................................................... 213
About the Transparent Proxy ....................................................................................................... 213
Creating an Explicit Proxy Server ................................................................................................ 214

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Contents

Using the ProxySG as an Explicit Proxy ............................................................................... 214
Configuring Adapter Proxy Settings..................................................................................... 215
Transparent Proxies........................................................................................................................ 215
Configuring Transparent Proxy Hardware.......................................................................... 216
Configuring a Layer-4 Switch ................................................................................................ 217
Configuring a WCCP-Capable Router.................................................................................. 217
Configuring IP Forwarding........................................................................................................... 217
Glossary
Index

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Volume 2: Proxies and Proxy Services

x

Chapter 1: Introduction

This volume provides information about proxy filters. A proxy filters traffic,
monitors Internet and intranet resource usage, blocks specific Internet and
intranet resources for individuals or groups, and enhances the quality of
Internet or intranet user experiences.
A proxy serves as an intermediary between a Web client and a Web server and
can require authentication to allow identity-based policy and logging for the
client, as discussed in Volume 4: Securing the Blue Coat ProxySG Appliance™.

About This Book
This book deals with the following topics:


Chapter 2: "About Management Services" on page 15



Chapter 3: "About Proxy Services and Proxies" on page 27



Chapter 4: "Accelerating File Sharing" on page 59



Chapter 5: "Managing the Domain Name Service (DNS) Proxy" on page 79



Chapter 6: "Accelerating the Microsoft Outlook Application (Endpoint
Mapper and MAPI Proxies)" on page 83



Chapter 7: "Managing the File Transport Protocol (FTP) Proxy" on page
101



Chapter 8: "Intercepting and Optimizing HTTP Traffic" on page 111



Chapter 9: "Configuing and Managing an HTTPS Reverse Proxy Service"
on page 151



Chapter 10: "Managing Shell Proxies" on page 159



Chapter 11: "Managing a SOCKS Proxy" on page 167



Chapter 12: "Managing the SSL Proxy" on page 177



Chapter 13: "Managing the TCP Tunneling Proxy" on page 207



Appendix A: "Explicit and Transparent Proxy" on page 213

Document Conventions
The following table lists the typographical and Command Line Interface (CLI)
syntax conventions used in this manual.
Table 1–1 Document Conventions

Conventions

Definition

Italics

The first use of a new or Blue Coat-proprietary term.

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Volume 2: Proxies and Proxy Services
Table 1–1 Document Conventions (Continued)
Courier font

Screen output. For example, command line text, file names, and
Blue Coat Content Policy Language (CPL).

Courier Italics

A command line variable that is to be substituted with a literal
name or value pertaining to the appropriate facet of your
network system.

Courier Boldface

A Blue Coat literal to be entered as shown.

Arial Boldface

Screen elements in the Management Console.

{ }

One of the parameters enclosed within the braces must be
supplied

[ ]

An optional parameter or parameters.

|

Either the parameter before or after the pipe character can or
must be selected, but not both.

Notes and Warnings
The following is provided for your information and to caution you against actions
that can result in data loss or personal injury:
Note: Information to which you should pay attention.

Important:

Critical information that is not related to equipment damage or
personal injury (for example, data loss).

WARNING! Used only to inform you of danger of personal injury or physical
damage to equipment. An example is a warning against electrostatic discharge
(ESD) when installing equipment.

About Procedures
Many of the procedures in this volume begin:


Select Configuration > TabName,

if you are working in the Management Console,

or


From the (config) prompt, if you are working in the command line interface (CLI).

Blue Coat assumes that you are logged into the first page of the Management
Console or entered into configuration mode in the CLI.

Illustrations
To save space, screen shots illustrating a procedure often have the bottom portion
removed, along with the blank space.

12

Chapter 1: Introduction

Figure 1–1

Configuration > General Tab with Bottom Buttons

Preview:



Click this button to view the configuration changes before applying
the configuration to the ProxySG. To modify your changes, click Close and
return to the the tab whose settings you want to modify.



Apply:



Revert:



Help: Click this button to view conceptual and procedural documentation
about the tab’s topic.

Click this button to apply unsaved configuration changes to the
ProxySG.
Click this button to revert any unapplied changes to the ProxySG
configuration. Changes that previously have been applied to the ProxySG are
not affected.

Figure 1–2

Configuration > General Tab with Bottom Buttons Removed

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Volume 2: Proxies and Proxy Services

14

Chapter 2: About Management Services

This chapter discusses how to configure and enable managment service
listeners.

Topics in this Chapter
This chapter includes information about the following topics:


"Overview of Management Services" on page 15



"Creating a Management Service" on page 16



"Managing the HTTP Console" on page 18



"Managing the HTTPS Console (Secure Console)" on page 18



"Managing the SNMP Console" on page 20



"Managing the SSH Console" on page 20



"Managing the Telnet Console" on page 24

Overview of Management Services
The ProxySG ships with management services (consoles) that are designed to
manage communication with the system:


HTTP and HTTPS Consoles: These consoles are designed to allow you
access to the Management Console. The HTTPS Console is created and
enabled by default; the HTTP Console is created by default but not enabled
because it is less secure than HTTPS.



SSH Console: This console is created and enabled by default, allowing you
access to the CLI using an SSH client.



SNMP Console: This console is created by default, but disabled. SNMP
listeners set up the UDP and TCP ports the ProxySG uses to listen for
SNMP commands.



Telnet Console: This console not created because the passwords are sent
unencrypted from the client to the ProxySG. You must create and enable
the console before you can access the appliance through a Telnet client (not
recommended).

Table 2–1 Management Services

Management
Service

Default Port

Status

Configuration Discussed

HTTPS-Console

8082

Enabled

"Managing the HTTPS Console (Secure Console)"
on page 18.

SSH-Console

22

Enabled

"Managing the SSH Console" on page 20

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Volume 2: Proxies and Proxy Services
Table 2–1 Management Services (Continued)

Management
Service

Default Port

Status

Configuration Discussed

HTTP-Console

8081

Disabled

"Managing the HTTP Console" on page 18

SNMP

161

Disabled

"Managing the SNMP Console" on page 20

Telnet-Console



Not
Created

"Managing the Telnet Console" on page 24

Creating a Management Service
Management services are used to manage the ProxySG. As such, bypass entries
are ignored for connections to console services.
To edit or create a management service:

1. Select Configuration > Services > Management Services.

2. To enable or disable a service, select or de-select the Enable option.
3. To change other settings on a specific console, highlight the service and click
Edit.
4. To create a new console service, click New.
Note: The HTTP Console is used in this example.

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Volume 2: Proxies and Proxy Services

SGOS (config service_name)
{enable | disable}
SGOS (config service_name)
port_number
SGOS (config service_name)
SGOS (config service_name)
SGOS (config service_name)
SGOS (config service_name)

add {all | proxy-ip_address} port_number
disable {all | proxy-ip_address}
enable {all | proxy-ip_address} port_number
exit
remove {all | proxy-ip_address} port_number
view

Managing the HTTP Console
The default HTTP Console is already configured; you only need to enable it.
You can create and use more than one HTTP Console as long as the IP address
and the port do not match the existing HTTP Console settings.
To create a new HTTP Console service or edit an existing one, see "Creating a
Management Service" on page 16.

Managing the HTTPS Console (Secure Console)
The HTTPS Console provides secure access to the Management Console through
the HTTPS protocol.
You can create multiple management HTTPS consoles, allowing you to
simultaneously access the Management Console using any IP address belonging
to the ProxySG as well as any of the appliance’s virtual IP (VIP) addresses. The
default is HTTPS over port 8082.
Creating a new HTTPS Console port requires three steps, discussed in the
following sections:


Selecting a keyring (a key pair and a certificate that are stored together)



Selecting an IP address and port on the system that the service will use,
including virtual IP addresses



Enabling the HTTPS Console Service

Selecting a Keyring
The ProxySG ships with a default keyring that can be reused with each console
that you create. You can also create your own keyrings.
To use the default keyring, accept the default keyring through the Management
Console. If using the CLI, the default keyring is automatically used for each new
HTTPS Console that is created.To use a different keyring you must edit the
console service and select a new keyring using the attribute keyring command.
Note: When using certificates for the HTTPS Console or for HTTPS termination
services that are issued by Certificate Signing Authorities that are not wellknown, see Chapter 9: "Configuing and Managing an HTTPS Reverse Proxy
Service" on page 151.

If you get “host mismatch” errors or if the security certificate is called out as
invalid, create a different certificate and use it for the HTTPS Console.

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Volume 2: Proxies and Proxy Services

Note: Two keyrings: configuration-passwords-key keyring an applicationkey keyring cannot be used for console services.

4. (Optional) Select the appropriate checkboxes to determine the SSL version
used for this console.
5. Configure the new listener options:
a. Click New to view the New Listener dialog. A listener defines the fields
where the console service will listen for traffic.
b. Select a destination option:


All ProxySG IP addresses—Indicates



IP Address—Indicates

that service listens on all addresses.

that only destination addresses match the IP

address.
c. Port—Identifies the port you want this service to listen on. Port 8081 is
the default port.
d. Enabled—Select this option to enable the listener.
e. Click OK to close the New Listener dialog.
6. Click OK to close the Edit Service dialog.
7. Click Apply.

Managing the SNMP Console
There is one disabled SNMP listener defined by default on the ProxySG, which
you can delete or enable, as needed. You can also add additional SNMP services
and listeners. Enabling SNMP listeners sets up the UDP and TCP ports on which
the ProxySG listens for SNMP commands.
To create and enable an SNMP service:

1. Select Configuration > Services > Management Services. The Management Services
tab displays.
2. Click Add. The New Service dialog displays.
3. Follow steps 2–5 in the section titled "Creating a Management Service" on
page 16.

Managing the SSH Console
By default, the ProxySG uses Secure Shell (SSH) and password authentication so
administrators can access the CLI or Management Console securely. SSH is a
protocol for secure remote logon over an insecure network.
When managing the SSH console, you can:

20



Enable or disable a version of SSH



Generate or re-generate SSH host keys

Chapter 2: About Management Services



Create or remove client keys and director keys



Specify a welcome message for clients accessing the ProxySG using SSHv2.

To create a new SSH Console service or edit an existing one, see "Creating a
Management Service" on page 16.

Managing the SSH Host
You can manage the SSH host connection either through the Management
Console or the CLI.
To manage the SSH host:
Note: By default, SSHv2 is enabled and assigned to port 22. You do not need to

create a new host key unless you want to change the existing configuration.
SSHv1 is disabled by default.
1. Select Configuration > Authentication > Console Access > SSH Host.

To delete a host key pair:

Click the Delete button for the appropriate version of SSH.
The key pair is deleted and that version of SSH is disabled.

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Volume 2: Proxies and Proxy Services

Note: If you disable both SSHv1 and SSHv2, you could be locked out of the CLI,
requiring you to re-create an SSH key pair using the terminal console. (You can recreate the SSH keys through the Management Console.)
SGOS (config ssh-console) create host-keypair

{sshv1| sshv2 | }

To create a host key pair:

Click the Create button for the appropriate version of SSH.
The new key pair is created and that version of SSH is enabled. The new key pair
is displayed in the appropriate pane.
Note: If you receive an error message when attempting to log in to the system

after regenerating the host key pair, locate the ssh known hosts file and delete the
system’s IP address entry.
To create an SSHv2 Welcome Banner:

1. In the SSHv2 Welcome Banner field, enter a line of text that will be displayed on
the ProxySG when a user attempts to log in to the system. If the message
length spans multiple lines, the ProxySG automatically formats the string for
multiline capability. The maximum size of the message can be up two
thousand characters and can include embedded newlines.
To delete the welcome banner, remove the text from the SSHv2 Welcome Banner
field.
2. Click Apply.

Managing SSH Client Keys
You can import multiple RSA client keys on the ProxySG to provide public key
authentication, an alternative to using password authentication. An RSA client
key can only be created by an SSH client and then imported onto the ProxySG.
Many SSH clients are commercially available for UNIX and Windows.
Once you create an RSA client key following the instructions of your SSH client,
you can import the key onto the ProxySG using either the Management Console
or the CLI. (For information on importing an RSA key, see "To import RSA client
keys:" on page 23.)

About the OpenSSH.pub Format
Blue Coat supports the OpenSSH.pub format. Keys created in other formats will not
work.
An OpenSSH.pub public key is similar to the following:
ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAIEAwFI78MKyvL8DrFgcVxpNRHMFKJrBMeBn
2PKcv5oAJ2qz+uZ7hiv7Zn43A6hXwY+DekhtNLOk3HCWmgsrDBE/NOOEnDpLQjBC6t/
T3cSQKZjh3NmBbpE4U49rPduiiufvWkuoEiHUb5ylzRGdXRSNJHxxmg5LiGEiKaoELJfsD
Mc= [email protected]

The OpenSSH.pub format appends a space and a user ID to the end of the client key.

22

Chapter 2: About Management Services

The user ID used for each key must be unique.
Other caveats:


1024 bits is the maximum supported key size.



An ssh-rsa prefix must be present.



Trailing newline characters must be removed from the key before it is
imported.

To import RSA client keys:

1. From your SSH client, create a client key and copy it to the clipboard.
Note: The above step must be done with your SSH client. The ProxySG

cannot create client keys.
2. Select Configuration > Authentication > Console Access > SSH Client.

3. Click Import to import a new client key.

4. Specify whether the client key is associated with an existing user or a new
user, and enter the name.
5. Paste the RSA key that you previously created with an SSH client into the
Client key field. Ensure that a key ID is included at the end. Otherwise, the
import fails.
6. Click OK.

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Volume 2: Proxies and Proxy Services

The SSH Client tab reappears, with the fingerprint (a unique ID) of the
imported key displayed.

7. Click Apply.

Related CLI Syntax to Manage the SSH Host and Client
SGOS (config) ssh-console


The following subcommands are available for managing key pairs and other
global options:
SGOS (config ssh-console) create host-keypair {sshv1| sshv2 | }
SGOS (config ssh-console) delete {client-key username key_id | legacyclient-key key_id | director-client-key key_id | host-keypair {sshv1 |
sshv2 | }}
SGOS (config ssh-console) inline {client-key | director-clientkey | sshv2-welcome-banner }
SGOS (config ssh-console) no sshv2-welcome-banner
SGOS (config ssh-console) view {client-key | director-client-key |
host-public-key | sshv2-welcome-banner | user-list | versions-enabled}

Managing the Telnet Console
The Telnet console allows you to connect to and manage the ProxySG using the
Telnet protocol. Remember that Telnet is an insecure protocol and should be used
only in very secure environments. By default, the Telnet Console is not created.
Blue Coat Systems recommends against using Telnet because of the security hole
it creates.
Note: If you do enable the Telnet console, be aware that you cannot use Telnet

everywhere in the CLI. Some modules, such as SSL, respond with the error
message:
Telnet sessions are not allowed access to ssl commands.

By default a Telnet shell proxy service exists on the default Telnet port (23). Since
only one service can use a specific port, you must delete the shell service if you
want to create a Telnet console. Be sure to apply any changes before continuing. If
you want a Telnet shell proxy service in addition to the Telnet console, you can recreate it later on a different port. For information on the Telnet service, see
Chapter 10: "Managing Shell Proxies" on page 159.

24

Chapter 2: About Management Services

To create a new Telnet console service or edit an existing one, see "Creating a
Management Service" on page 16.
Note: To use the Telnet shell proxy (to communicate with off-proxy systems)
and retain the Telnet Console, you must either change the Telnet shell proxy to
use a transparent Destination IP address, or change the destination port on
either the Telnet Console or Telnet shell proxy. Only one service is permitted
on a port. For more information on the Telnet shell proxy, see Chapter 10:
"Managing Shell Proxies" on page 159.

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Volume 2: Proxies and Proxy Services

26

Chapter 3: About Proxy Services and Proxies

This chapter discusses proxies, proxy services and service groups. It also
describes how to configure a basic proxy service.

Topics in this Chapter
This chapter includes information about the following topics:


Section A: "Managing Proxy Services and Service Groups" on page 34



Section B: "Creating or Editing a Proxy Service" on page 37



Section C: "About Global Options for Proxy Services" on page 43



Section D: "About the Bypass List" on page 49



Section E: "Using Restricted Intercept" on page 53



Section F: "Proxy Services and Listeners" on page 55

For additional information about configuring and managing a specific proxy
service see:


Chapter 4: "Accelerating File Sharing" on page 59



Chapter 5: "Managing the Domain Name Service (DNS) Proxy" on page 79



Chapter 6: "Accelerating the Microsoft Outlook Application (Endpoint
Mapper and MAPI Proxies)" on page 83



Chapter 7: "Managing the File Transport Protocol (FTP) Proxy" on
page 101



Chapter 8: "Intercepting and Optimizing HTTP Traffic" on page 111



Chapter 9: "Configuing and Managing an HTTPS Reverse Proxy Service"
on page 151



Chapter 10: "Managing Shell Proxies" on page 159



Chapter 11: "Managing a SOCKS Proxy" on page 167



Chapter 12: "Managing the SSL Proxy" on page 177



Chapter 13: "Managing the TCP Tunneling Proxy" on page 207

After setting up and enabling the proxy service, the next step is to configure the
proxy for your environment. If necessary, you can configure bypass lists for
transparent proxy environments. Alternatively, you can specify a list of services
that you do want intercepted.

About Proxies and Proxy Services
A proxy filters traffic, monitors Internet and intranet resource usage, blocks
specific Internet and intranet resources for individuals or groups and enhances
the quality of Internet or intranet user experiences.

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Volume 2: Proxies and Proxy Services

A proxy serves as an intermediary between a Web client and a Web server and can
require authentication to allow identity-based policy and logging for the client, as
discussed in Volume 4: Securing the Blue Coat ProxySG Appliance.
Proxy services define the ports and addresses where a ProxySG™ listens for
incoming requests. A variety of attributes for each service can be defined. Each
service can be applied to all IP addresses or limited to a specific set of addresses
and port combinations. A number of default services are predefined. Additional
services can be defined on other ports.
Blue Coat has two types of services: proxy services, used to communicate with
other systems and console services, used to communicate with the ProxySG.
Note: Console services are discussed in Chapter 2: "About Management

Services" on page 15.

About Proxy Listeners
A proxy listener is the location where the ProxySG listens for traffic for a specific
service. It identifies network traffic based on a destination IP address criterion, a
destination port or port range and an action to perform on that traffic. A proxy
listener can be identified by any destination IP/subnet and port range, and
multiple listeners can be added for each service.
Note: A proxy listener should not be confused with the Default proxy listener, a
service that intercepts all traffic not otherwise intercepted by other listeners.

Four settings are available (some settings are not available for some proxy
listeners):


All: This service attribute enables all IP addresses to be intercepted.



Transparent: This listener type acts on connections without the client or server
being aware of it. Only connections to destination addresses that do not
belong to the ProxySG are intercepted. This setting requires a bridge, such as
that available in the ProxySG; a Layer-4 switch, or a WCCP-compliant router.
You can also transparently redirect requests through a ProxySG by setting the
workstation’s gateway to the appliance IP address.



Explicit: This listener type is the default and requires software configuration
for both browser and service. It sends requests explicitly to a proxy instead of
to the origin content servers. Only destinations addresses that match one of
the IP addresses on the ProxySG are intercepted.



Destination IP address or subnet: This listener type ensures that only
destination addresses matching the IP address and subnet are intercepted.
Some software configuration on the ProxySG is also required to allow the
appliance to know what traffic to intercept.

28

Chapter 3: About Proxy Services and Proxies

Note: For information on understanding explicit and transparent proxies and the

configuration requirements, see Appendix A: "Explicit and Transparent Proxy"
on page 213.
For a complete list of supported proxy services and listeners, see Section F: "Proxy
Services and Listeners" on page 55.

About Service Attributes and Proxy Services
The service attributes define the parameters the ProxySG uses for a particular
service.
The following table describes the attributes for a proxy service; however,
depending on the protocol, not all attributes are available for each proxy type.
Table 3–1 Service Attributes

Attribute

Description

Authenticate-401

All transparent and explicit requests received on the port
always use transparent authentication (cookie or IP, depending
on the configuration). This is especially useful to force
transparent proxy authentication in some proxy-chaining
scenarios.

CA-Cert List

CA Certificate List used for verifying client certificates.

Detect Protocol

Detects the protocol being used. Protocols that can be detected
include HTTP, P2P (eDonkey, BitTorrent, FastTrack, Gnutella),
SSL, and Endpoint Mapper. For more information on protocol
detection, see Chapter 13: "Managing the TCP Tunneling
Proxy" on page 207.

Early Intercept

Controls whether the proxy responds to client TCP connection
requests before connecting to the upstream server. When early
intercept is disabled, the proxy delays responding to the client
until after it has attempted to contact the server. If you enable the
Detect Protocol attribute, the Early Intercept attribute is selected
automatically.

Enable ADN

Controls whether ADN is enabled for a specific service.
Enabling ADN does not guarantee the connections are
accelerated by ADN. The actual enable decision is determined
by ADN routing (for explicit deployment) and network setup
(for transparent deployment).

Forward Client Cert

When used with the verify-client attribute, puts the extracted
client certificate information into a header that is included in
the request when it is forwarded to the OCS. The name of the
header is Client-Cert. The header contains the certificate serial
number, subject, validity dates and issuer (all as name=value
pairs). The actual certificate itself is not forwarded.

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Volume 2: Proxies and Proxy Services

Table 3–1 Service Attributes (Continued)

Attribute

Description

Optimize
Bandwidth

Controls whether to optimize bandwidth usage when
connecting upstream using an ADN tunnel.

SSL Versions

Allows you to select which versions of SSL you want to
support. The default is to support SSL v2, v3, and TLS. This
attribute is available for HTTPS Reverse Proxy.

Verify Client

Requests and validates the SSL client certificate. This attribute
is available for HTTPS Reverse Proxy.

About Multiple Listeners
A listener identifies network traffic based on a destination IP address criterion, a
destination port or port range and an action to perform on that traffic. Multiple
listeners can be defined for a proxy service or console service. Each service has a
set of default actions to apply to the traffic identified by the listeners it owns.
The destination IP address of a connection can match multiple proxy service
listeners. Multiple matches are resolved using the most-specific match algorithm
used by routing devices. A listener is more specific if it has a larger Destination IP
subnet prefix. For example, the subnet 10.0.0.0/24 is more specific than 10.0.0.0/
16, which is more specific than 10.0.0.0/8.
When a new connection is established, the ProxySG first finds the most specific
listener Destination IP. If a match is found, and the destination Port also matches,
the connection is then handled by that listener. If the destination Port of the
listener with the most specific Destination IP does not match, the next mostspecific Destination IP is found; this process continues until either a complete
match is found or no more matching addresses are found.
For example, assume the following services were defined:
Table 3–2 Example Configuration for Most Specific Match Algorithm

Proxy Service

Listener

Service Name

Proxy

Destination IP Address

Port Range

New York Data Center

HTTP

10.167.10.0/24

80

New York CRM

HTTP

10.167.10.2/32

80

HTTP Service

HTTP



80

An HTTP connection initiated to server 10.167.10.2 could match any of the three
listeners in the above table. The most specific match algorithm finds that a listener
in the New York CRM service is the most specific and since the destination port of
the connection and the listener match, the connection is handled by this service.

30

Chapter 3: About Proxy Services and Proxies

The advantage of the most specific match algorithm becomes evident when at
some later point another server is added in the New York Data Center subnet. If
that server needs to be handled by a different service than the New York Data
Center service, a new service with a listener specific to the new server would be
added. The administrator does not need to be concerned about rule order in order
to intercept traffic to this particular server using the new, most specific service
listener.

About Proxy Service Groups
Proxy services are defined on the Proxy Services page
(Configuation > Services > Proxy Services) and are grouped together into predefined
service groups based on the type of traffic they handle. Service groups allow you
to:


Turn on a group of predefined services



Turn on one listener at a time while maintaining the service grouping



Intercept traffic on a service group level



Create custom service groups



Create and assign a new service to a custom service group when a predefined
service group is not sufficient

See Table 3–3, "Service Groups and Services" on page 31 for a complete list of
service groups and their associated services.
Note: The HTTPS Reverse Proxy service is also available but not created by
default. For information about configuring the HTTPS Reverse Proxy, see
Chapter 9: "Configuing and Managing an HTTPS Reverse Proxy Service" on
page 151.

Predefined Service Groups and Services
Table 3–3, "Service Groups and Services" lists all service groups and their
associated services. All listed service groups are predefined (except Custom
Service Groups) and cannot be renamed or deleted. However, you can add a new
service to a predefined service group or move a service from one group to
another.
Table 3–3

Service Groups and Services

Services Group
Name

Services Group Description Predefined Services

Standard

Services that usually provide
content to users

FTP, HTTP, MMS, RTSP

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Volume 2: Proxies and Proxy Services

Table 3–3

Service Groups and Services

Services Group
Name

Services Group Description Predefined Services

Intranet

Services that usually
constitute intranet traffic

CIFS, Citrix ICA, Endpoint
Mapper, LDAP, Lotus Notes,
LDP, MS SQL Server, MySQL,
NFS, Novell GroupWise,
Novell NCP, Oracle, POP3,
SMTP, SnapMirror, Sybase SQL

Encrypted

Services that contain
encrypted data and therefore
should not be ADNoptimized

HTTPS, IMAPS, POP3S

Interactive

Services where the data is
interactive

MS Terminal Services, Shell,
SSH, Telnet, VNC, X Windows

Reverse-proxy

Placeholder for setting up a
reverse proxy deployment

none

Other

Other services the ProxySG
can monitor

AOL-IM, MSN IM, Yahoo IM,
DNS, SOCKS, default.

About Protocol Detection
Protocol detection identifies HTTP, SSL, Endpoint Mapper and various P2P
protocols carried within HTTP CONNECT requests, SOCKS CONNECT requests,
and TCP tunnels. On the ProxySG, protocol detection can be enabled or disabled for
each proxy service manually or it can be implemented using policy. If you set
policy for protocol detection, you can enhance granularity by matching on a
richer set of conditions than just the specific service; policy always overrides
manual settings.
If protocol detection is enabled, the ProxySG inspects the first bytes sent from the
client and determines if a corresponding application proxy is available to hand off
the connection. For example, an HTTP request identified on a TCP tunnel has full
HTTP policy applied to it, rather than just simple TCP tunnel policy. In particular,
this means that:

32



The request shows up as client protocol HTTP rather than TCP Tunnel.



The URL used while evaluating policy is an http:// URL of the tunneled
HTTP request, not a tcp:// URL of where the tunnel was connecting to.



Forwarding policy is applied based on the new HTTP request, so the
forwarding host selected must support HTTP. A forwarding host of type TCP
cannot handle the request and causes the request to be blocked.

Chapter 3: About Proxy Services and Proxies

Enabling protocol detection helps accelerate the flow of traffic. However, the TCP
session must be fully established with the client before either the application
proxy or the TCP tunnel proxy contacts the origin server. In some cases, like in the
active-mode FTP data connections, enabling protocol detection may cause a delay
in setting up the connection.
You can avoid this connection delay either by using a protocol specific proxy such
as the FTP proxy or by disabling protocol detection.
If protocol detection is disabled, either in the proxy service check box or through
policy, traffic flows over a TCP tunnel without being accelerated by a protocol
specific proxy.

33

Chapter 3: About Proxy Services and Proxies
Section A: Managing Proxy Services and Service Groups

Moving a Service Among Groups
To move a service from one service group to another:

1. From the Management Console, select Configuration > Services > Proxy Services.
2. On the Proxy Services tab, expand the service group where the service you
want to move resides.

3. Select the service you want to move and click Move Service. The Move Service
dialog displays.
4. From the drop-down menu, select the service group into which you want to
move the service.
5. Click OK to close the dialog; click Apply. The service now resides in elected
service group.

Deleting a Service or Service Group
To delete a service:

1. On the Proxy Services tab, select the service or custom service group you want
to delete.
2. Click Delete. A prompt appears asking if you want to delete the selected
service.
3. Click Yes. The selected service or custom service group is deleted.

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Volume 2: Proxies and Proxy Services
Section A: Managing Proxy Services and Service Groups

Note: You can delete a service within a predefined service group but you cannot

delete an empty predefined service group itself. However, you can delete the
Custom service group if it is empty.
You can add back a default service you deleted from the service library by using
the Import Service feature. See "" on page 41.

Relevant CLI Syntax to Create and Configure a Service Group


To enter configuration mode for the service:
SGOS#(config) service-groups



The following subcommands are available:
SGOS#(config service-groups){create|bypass-all|delete|intercept-all|
view}
SGOS#(config service-groups) view

36

Chapter 3: About Proxy Services and Proxies
Section B: Creating or Editing a Proxy Service

Section B: Creating or Editing a Proxy Service
This section describes how to create a new or edit an existing proxy service. Only
general instructions are given as each specific proxy service has configuration
differences.

Creating a New Proxy Service
To create a new proxy service:

1. From the Management Console, select Configuration > Services > Proxy Services.
The Proxy Services tab displays.
2. At the bottom of the tab, click New Service. The New Service dialog displays.
Note: If you only want to change the proxy’s behavior from bypass (the default)
to intercept, go to the Action column of the Proxy Services pane, select the service
whose behavior you want to change, and click Intercept from the drop-down list.
You do not need to enter New/Edit mode to change this setting.

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Volume 2: Proxies and Proxy Services
Section B: Creating or Editing a Proxy Service
.

2. Scroll the list of service groups and click a service group to expand.

3

3. Select the service whose configuration you want to edit and then click Edit
Service at the bottom of the page. The Edit Service dialog displays.
4. Edit the fields and click OK.

Importing a Service from the Service Library
If needed, you can import a service from the service library. This is useful if you
delete a default service and want to add it back. The list of default services on the
Proxy Services tab is identical to those in the services library.
To import a service from the service library:

1. From the Management Console, select Configuration > Services > Proxy Services.
2. On the Proxy Services tab, click Import Service. The Import Service dialog displays.

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Volume 2: Proxies and Proxy Services
Section B: Creating or Editing a Proxy Service
SGOS#(config proxy-services) create {aol-im | cifs | dns | endpointmapper | ftp | http | https-reverse-proxy | mms | msn-im | rtsp | socks
| ssl | tcp-tunnel | telnet | yahoo-im} service-name service-group
SGOS#(config proxy-services) edit service-name


The following subcommands are available:
SGOS#(config service-name) add {transparent | explicit | all |
ip_address | ip_address/subnet-mask} {port | first_port-last_port}
[intercept | bypass]
SGOS#(config service-name) attribute {authenticate-401 | adn-optimize
| ccl | cipher-suite | detect-protocol | early-intercept | forwardclient-cert | keyring | ssl-versions | use-adn | verify-client}
SGOS#(config
ip_address |
SGOS#(config
SGOS#(config
ip_address |
SGOS#(config
SGOS#(config
ip_address |

service-name) bypass {transparent | explicit | all |
ip_address/subnet-mask} {port | first_port-last_port}
service-name) group service-group
service-name) intercept {transparent | explicit | all |
ip_address/subnet-mask} {port | first_port-last_port}
service-name) proxy-type proxy-type
service-name) remove {transparent | explicit | all |
ip_address/subnet-mask} {port | first_port-last_port}

SGOS#(config service-name) view


To import a predefined service into a service group from the services library:
SGOS#(config proxy-services) import predefined service-name



The following subcommands are available:
SGOS#(config proxy-services) import predefined service-name overwrite

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Volume 2: Proxies and Proxy Services
Section C: About Global Options for Proxy Services

Section C: About Global Options for Proxy Services
Blue Coat provides three global option settings for proxy services:


Reflecting the client’s source IP when connecting to servers
The Reflect Client IP option determines how the client IP address is presented
to the origin server for all requests. Enable this option when you want the
client’s IP address sent to the origin server instead of the ProxySG’s IP
address.
Note: The Reflect Client IP option is only supported in transparent ProxySG
deployments.



Trusting the Destination IP Address Provided by the Client
If, in your environment, a client sometimes provides a destination IP address
that the ProxySG appliance cannot determine, you can configure the ProxySG
to allow that IP address and not do a DNS lookup. This can improve
performance (but potentially cause a security issue).



Managing User Limits
If you have more users going through the system than is allowed by the model
license, you can configure overflow behavior to be queued or to bypass the
ProxySG.

Reflecting the Client Source IP when Connecting to Servers
You can globally turn on the Reflect Client IP option for all services that will be
intercepted. To turn on the Relfect Client IP option for only a few services, first
enable this option globally and then create policy to disable the Reflect Client IP
option for the exceptions. Or, disable the option globally and create policy to
enable it.

Trusting the Destination IP Address Provided by the Client
You can configure the ProxySG appliance to trust a client-provided destination IP
address in transparent proxy deployments where:


The DNS configuration on the client is correct, but is not correct on the
ProxySG.



The client obtains the destination IP address using WINS or DNS imputing on
the ProxySG is not configured correctly. In these cases, the appliance cannot
obtain the destination IP address to serve the client request.

You can use the client-provided destination IP address with transparent proxy
environments that use HTTP, native FTP, WebFTP, HTTPS, or streaming.
The ProxySG cannot trust the client-provided destination IP address in the
following situations:

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Volume 2: Proxies and Proxy Services
Section C: About Global Options for Proxy Services


The ProxySG receives the client requests in an explicit proxy deployment.



The ProxySG has a forwarding rule configured for the request.



The ProxySG has a SOCKS gateway rule configured for the request.



The ProxySG has ICP enabled for the request.



The ProxySG has policy that rewrites the server URL

.

Note: If you are using an Application Delivery Network (ADN), this setting is enforced
on the concentrator proxy through the Configuration > Proxy Settings> General tab. For
more information, refer to Volume 5: Advanced Networking.

Enabling the ProxySG to Trust the Client-Provided Destination IP
Address
Defaults:


Proxy Edition: the ProxySG appliance does not trust a client-provided
destination IP address.



MACH5 Edition: The ProxySG appliance trusts client-provided destination IP
addresses.

You can change this default through the Management Console (Configuration >
the CLI, or through policy. If you use policy, be aware that
it overrides any other configuration. For information about using the
trust_destination_ip(yes|no) property, refer to Volume 10: Blue Coat SG
Appliance Content Policy Language Guide.
Proxy Settings > General)

Note: For the MACH5 edition, the ProxySG allows the client-provided

destination IP address by default.
For information about enabling the ProxySG to allow the client-provided
destination IP address, see "Configuring General Options" on page 47.

Tip
If a client gives the destination address of a blocked site but the hostname of a
non-blocked site, the ProxySG connects to the destination address. This might
allow clients to bypass the configured appliance security policy.

Managing User Limits
If your ProxySG is in demo or trial mode, an unlimited number of users can have
connections processed by the system at the same time.
After a permanent model license has been applied to the system, the license
controls the number of active users who can have connections processed by the
system at the same time The number of users depends on whether ADN is
enabled and on the hardware model.

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Volume 2: Proxies and Proxy Services
Section C: About Global Options for Proxy Services

Only unique IP addresses of connections intercepted by proxy services are
counted toward the user limit. The number of permitted users is illustrated in the
table below.
Table 3–4 Hardware Models and Licensed Users

Hardware Model

Number of Users
(Without ADN Enabled)

Number of Users (With
ADN Enabled)

210-5

30

10

210-10

150

50

210-25

Not License Limited

Not License Limited

510-5

200

50

510-10

500

125

510-20

1200

300

510-25

Not License Limited

Not License Limited

810-5

2500

500

810-10

3500

700

810-20

5000

1000

810-25

Not License Limited

Not License Limited

8100-5

Not License Limited

Not License Limited

8100-10

Not License Limited

Not License Limited

8100-20, 8100-20-DC

Not License Limited

Not License Limited

Determining Behavior if User Limits are Exceeded
If you have more user connections going through the system simultaneously than
is allowed by the model license, you can configure overflow behavior in the
following ways:


Bypassing the system: All connections exceeding the maximum are passed
through the system without processing.



Queuing connections: All connections exceeding the maximum are queued,
waiting for another connection to drop off.



Not enforcing the licensed-user limit: This is the default value.
Note: SGOS 5.2.1 and later has two options only: Queue and Bypass. Queue is

the default.
To set the preferred behavior, see "Configuring General Options" on page 47.

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Volume 2: Proxies and Proxy Services
Section C: About Global Options for Proxy Services

Setting User Limits Notifications
You can set and monitor user limits of the model license through the Maintenance >
Health Monitoring > Licensing tab, including setting thresholds (in percentages) to be
notified if the user limits are nearing the upper user limits.
Note: You can use the Statistics > Health Monitoring > Licensing tab to view licensing

metrics, but you cannot make changes to the threshold values from that tab. To
change the thresholds, use the Maintenance > Health Monitoring > Licensing tab.
To view licensing metrics and set user limits notifications:

1. Click Maintenance > Health Monitoring > Licensing.

2. Select the license to edit.
3. Click Edit.
4. Modify the threshold values. Note that the thresholds represent the
percentage of license utilization.
a. To change the critical threshold, enter a new value in the Critical
Threshold field.
b. To change the critical interval, enter a new value in the Critical Interval
field.
c. To change the warning threshold, enter a new value in the Warning
Threshold field.
d. To change the warning interval, enter a new value in the Warning
Interval field.
5. Select the notification settings.


46

Log

adds an entry to the Event log.

Chapter 3: About Proxy Services and Proxies
Section C: About Global Options for Proxy Services



Trap



Email

sends an SNMP trap to all configured management stations.
sends an e-mail to the addresses listed in the Event log properties.

6. Click OK.
7. Click Apply.
For information about licensing metrics, refer to Volume 9: Managing the ProxySG.

Related CLI Syntax to Manage User Limits
SGOS#(config) alert notification license-utilization users {email |
log | trap | none}
SGOS#(config) alert threshold license-utilization users warn-threshold
warn-interval crit-threshold crit-interval

Viewing Concurrent Users
View a snapshot of intercepted, concurrent users by selecting the Statistics > System
> Resources > Concurrent Users tab. The tab shows user connections going through
the ProxySG appliance for the last 60 minutes, day, week, month, and year. Only
unique IP addresses of connections intercepted by proxy services are counted
toward the user limit.

Configuring General Options
You can configure the Reflect Client IP and Trust Destination IP options and the
behavior if user limits are exceeded on the Configuration > Proxy Settings > General
tab. For detailed information about these options, see Section C: "About Global
Options for Proxy Services" on page 43.
To configure General options:

1. Click Configuration > Proxy Settings > General.

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Volume 2: Proxies and Proxy Services
Section C: About Global Options for Proxy Services

2. Select or clear the Reflect client’s source IP when connecting to servers option.
3. Select or clear the Trust client-provided destination IP when connecting to servers
option.
4. Click the radio button for the User Overflow Action you prefer when the
licensed-user limits are exceeded. By default, for SGOS 5.2.2 and later, none is
the default.
Note: If you set the User Overflow Action to none and exceed the licensed-user
limits, the ProxySG health changes to CRITICAL.

5. Click Apply.

Related CLI Syntax to Manage Reflect Client IP and User Limit
Notifications
SGOS#(config) general
SGOS#(config general) reflect-client-ip {enable | disable}
SGOS#(config general) trust-destination-ip {enable | disable}
SGOS#(config general) user-overflow-action {bypass | none | queue}

See Also

48



"About Global Options for Proxy Services"



"Reflecting the Client Source IP when Connecting to Servers"



"Trusting the Destination IP Address Provided by the Client"



"Managing User Limits"

Chapter 3: About Proxy Services and Proxies

Section D: About the Bypass List
The bypass list contains IP addresses/subnet masks of client and server
workstations. Used only in a transparent proxy environment, the bypass list
allows the ProxySG to skip processing requests sent from specific clients to
specific servers. The list allows traffic between protocol incompliant clients and
servers to pass through the ProxySG without a disruption in service.
Note: This prevents the appliance from enforcing any policy on these requests

and disables any caching of the corresponding responses. Because bypass entries
bypass Blue Coat policy, use bypass sparingly and only for specific situations.

Adding Static Bypass Entries
You can add entries to prevent the requests from specified systems from being
intercepted by the ProxySG.
Note: Dynamic bypass cannot be configured through the Management
Console. It can only be configured through policy or the CLI. For more
information, see “ Using Policy to Configure Dynamic Bypass” on page 50.
To add static bypass entries:

1. Click Configuration > Services > Proxy Services > Static Bypass List.
2. Click New to create a new list entry; click Edit to modify a list entry.

3. Fill in the fields:
a. Select a source IP address from the drop-down list or choose .
Add the subnet mask.
b. Select a destination IP address from the drop-down list or choose
. Add the subnet mask.
4. Click OK; click Apply.

Relevant CLI Syntax to Manage Static Bypass Entries


To configure the service:
SGOS#(config) proxy-services
SGOS#(config proxy-services) static-bypass



The following subcommands are available:

49

Volume 2: Proxies and Proxy Services

SGOS#(config static-bypass) add {all | client_ip_address |
client_ip_address/subnet-mask} {all | server_ip_address |
server_ip_address/subnet-mask}
SGOS#(config static-bypass) remove {all | client_ip_address |
client_ip_address/subnet-mask} {all | server_ip_address |
server_ip_address/subnet-mask}
SGOS#(config static-bypass) view {filter {* | all | client_ip_address
| client_ip_address/subnet-mask} {* | all | server_ip_address |
server_ip_address/subnet-mask} | }

Using Policy to Configure Dynamic Bypass
Dynamic bypass, available through policy, can automatically compile a list of
response URLs that return various kinds of errors.
Note: Because bypass entries bypass Blue Coat policy, the feature should be used
sparingly and only for specific situations.

Dynamic bypass keeps its own (dynamic) list of which connections to bypass,
where connections are identified by both source and destination. Dynamic bypass
can be based on any combination of policy triggers. In addition, some global
settings can be used to selectively enable dynamic bypass based on specific HTTP
response codes. After an entry exists in the dynamic bypass table for a specific
source/destination IP pair, all connections from that source IP to that destination
IP are bypassed in the same way as connections that match against the static
bypass list.
For a configured period of time, further requests for the error-causing URLs are
sent immediately to the origin content server (OCS), bypassing the ProxySG. The
amount of time a dynamic bypass entry stays in the list and the types of errors
that cause the ProxySG to add a site to the list, as well as several other settings, are
configurable from the CLI.
Once the dynamic bypass timeout for a client and server IP address entry has
ended, the ProxySG removes the entry from the bypass list. On the next client
request for the client and server IP address, the ProxySG attempts to contact the
OCS. If the OCS still returns an error, the entry is once again added to the local
bypass list for the configured dynamic bypass timeout. If the entry does not
return an error, entries are again added to the dynamic list and not the local list.

Notes

50



Dynamic bypass entries are lost when the ProxySG is restarted.



No policy enforcement occurs on client requests that match entries in the
dynamic or static bypass list.



If a site that requires forwarding policy to reach its destination is entered into
the bypass list, the site is inaccessible.

Chapter 3: About Proxy Services and Proxies

Configuring Dynamic Bypass
Dynamic bypass is disabled by default. Enabling and fine-tuning dynamic bypass
is a two-step process:


Set the desired dynamic bypass timeout and threshold parameters.



Use policy (recommended) or the CLI to enable dynamic bypass and set the
types of errors that cause dynamic bypass to add an entry to the bypass list.

Adding Dynamic Bypass Parameters to the Local Bypass List
The first step in configuring dynamic bypass is to set the server-threshold,
max-entries, or timeout values.
Note: This step is optional because the ProxySG uses default configurations if

you do not specify them. Use the default values unless you have specific reasons
for changing them. Contact Blue Coat Technical Support for detailed advice on
customizing these settings.


The server-threshold value defines the maximum number of client entries
before the ProxySG consolidates client–server pair entries into a single server
entry that then applies to all clients connecting to that server. The range is 1 to
256. The default is 16. When a consolidation occurs, the lifetime of the
consolidated entry is set to the value of timeout.



The max-entries defines the maximum number of total dynamic bypass
entries. The range is 100 to 50,000. The default value is 10,000. When the
number of entries exceeds the max-entries value, the oldest entry is replaced
by the newest entry.



The timeout value defines the number of minutes a dynamic bypass entry can
remain unreferenced before it is deleted from the bypass list. The range is 1 to
86400. The default value is 60.

Enabling Dynamic Bypass and Specifying Triggers
Enabling dynamic bypass and specifying the types of errors that causes a URL to
be added to the local bypass list are done with the CLI. You cannot use the
Management Console.
Using policy to enable dynamic bypass and specify trigger events is better than
using the CLI, because the CLI has only a limited set of responses. For
information about available CLI triggers, refer to the Volume 11: Command Line
Interface Reference. For information about using policy to configure dynamic
bypass, refer to the Volume 10: Content Policy Language Guide.

Bypassing Connection and Receiving Errors
In addition to setting HTTP code triggers, you can enable connection and receive
errors for dynamic bypass.
If connect-error is enabled, any connection failure to the origin content server
(OCS), including timeouts, inserts the OCS destination IP address into the
dynamic bypass list.

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Volume 2: Proxies and Proxy Services

If receive-error is enabled, when the cache does not receive an HTTP response
on a successful TCP connection to the OCS, the OCS destination IP address is
inserted into the dynamic bypass list. Server timeouts can also trigger receiveerror. The default timeout value is 180 seconds, which can be changed (refer to
Volume 1: Getting Started).

Related CLI Syntax to Enable Dynamic Bypass and Trigger Events


To enter configuration mode for the service:
SGOS#(config) proxy-services
SGOS#(config proxy-services) dynamic-bypass



The following subcommands are available:
SGOS#(config dynamic-bypass) {enable | disable}
SGOS#(config dynamic-bypass) max-entries number
SGOS#(config dynamic-bypass) server-threshold number
SGOS#(config dynamic-bypass) trigger {all | connect-error | non-http |
receive-error | 400 | 403 | 405 | 406 | 500 | 502 | 503 | 504}
SGOS#(config dynamic-bypass) timeout minutes
#(config dynamic-bypass) no trigger {all | connect-error | non-http |
receive-error | 400 | 403 | 405 | 406 | 500 | 502 | 503 | 504}
SGOS#(config dynamic-bypass) clear
SGOS#(config dynamic-bypass) view

52

Chapter 3: About Proxy Services and Proxies

Section E: Using Restricted Intercept
By default, all clients and servers evaluate the entries in Proxy Services
(Configuration > Services > Proxy Services) where the decision is made to intercept or
bypass a connection. To restrict or reduce the clients and servers that can be
intercepted by proxy services, use the Restricted Intercept List. The Restricted
Intercept List is useful in a rollout, prior to full production, where you only want
to intercept a subset of the clients. After you are in full production mode, you can
disable the Restricted Intercept List.
The Restricted Intercept List is also useful when troubleshooting an issue, because
you can reduce the set of systems that are intercepted. If the restrict interception
radio button (Configuration > Services > Proxy Services > Restricted Intercept List) is
selected, any systems not on the list are bypassed.
If restricted intercept is disabled, the traffic behavior reverts to the previous
behavior (before the Restricted Intercept List was enabled). If restricted intercept
is enabled, traffic not in the list of systems is bypassed.
Note: An entry can exist in both the Static Bypass List and the Restricted

Intercept List. However, the Static Bypass List overrides the entries in the
Restricted Intercept List.
To configure a Restricted Intercept List:

1. Click Configuration > Services > Proxy Services > Restricted Intercept List.
2. Click Restrict Interception to the servers and clients listed below-- all other connections
are bypassed.
3. Click New to create a new list entry, or click Edit to modify a list entry.

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Volume 2: Proxies and Proxy Services

4. To select a specific client to be intercepted, click Client host or subnet and enter
the IP Address and Subnet Mask. To select all clients using a specific server, click
All clients, then enter the server IP Address and Subnet Mask in the Server address
section.
5. Click OK to close the dialog.
6. Click Apply.

Related CLI Syntax to Configure Restricted Intercept Lists


To enter configuration mode for the service:
SGOS#(config) proxy-services
SGOS#(config proxy-services) restricted-intercept



The following subcommands are available:
SGOS#(config restricted-intercept) {enable | disable}
SGOS#(config restricted-intercept) add {all | client_ip | client_ip/
subnet-mask} | {all| server_ip | server_ip/subnet-mask}
SGOS#(config restricted-intercept) remove {all | client_ip |
client_ip/subnet-mask} | all| server_ip | server_ip/subnet-mask}
SGOS#(config restricted-intercept) view { | filter {all |
client_ip | client_ip/subnet-mask} | {all| server_ip | server_ip/
subnet-mask}

54

Chapter 3: About Proxy Services and Proxies

Section F: Proxy Services and Listeners
Defaults:


Proxy Edition: Table 3–5, "Proxy Name and Listeners" on page 55 lists the
default ProxySG services and their default listeners. If you have an upgraded
appliance, all services existing before the upgrade are preserved.



MACH5 Edition:


A transparent TCP tunnel connection listening on port 23 is created in
place of the default Telnet service.



Instant messaging, HTTPS reverse proxy, SOCKS, and Telnet services are
not created on the MACH5 Edition ProxySG and are not included in trend
data.

Note: Console services, used to manage the ProxySG, are not discussed in this

chapter. For information about the four console services—HTTP, HTTPS, SSH,
and Telnet—see Chapter 2: "About Management Services" on page 16.
Table 3–5 Proxy Name and Listeners

Service
Name

Proxy

Destination
IP Address

Port Range

Configuration Discussed

AOL-IM

AOL-IM



5190

Volume 2: Proxies and Proxy
Services

CIFS

CIFS



445, 139

Chapter 4: "Accelerating File
Sharing" on page 59

Citrix ICA

TCP-Tunnel



1494

Chapter 13: "Managing the TCP
Tunneling Proxy" on page 207

DNS

DNS



53

Chapter 5: "Managing the
Domain Name Service (DNS)
Proxy" on page 79

Endpoint
Mapper

Endpoint
Mapper



135

Chapter 6: "Accelerating the
Microsoft Outlook Application
(Endpoint Mapper and MAPI
Proxies)" on page 83

FTP

FTP



21

Chapter 7: "Managing the File
Transport Protocol (FTP) Proxy"
on page 101

HTTP

HTTP



80



8080

Chapter 8: "Intercepting and
Optimizing HTTP Traffic" on page
111



443

HTTPS

SSL

Chapter 12: "Managing the SSL
Proxy" on page 177

55

Volume 2: Proxies and Proxy Services
Table 3–5 Proxy Name and Listeners (Continued)

Service
Name

Proxy

Destination
IP Address

Port Range

Configuration Discussed

IMAP

TCP-Tunnel



143

Chapter 13: "Managing the TCP
Tunneling Proxy" on page 207

IMAPS

TCP-Tunnel



993

Chapter 13: "Managing the TCP
Tunneling Proxy" on page 207

Kerberos

TCP-Tunnel



88

Chapter 13: "Managing the TCP
Tunneling Proxy" on page 207

LDAP

TCP-Tunnel



389

Chapter 13: "Managing the TCP
Tunneling Proxy" on page 207

LPD

TCP-Tunnel



515

Chapter 13: "Managing the TCP
Tunneling Proxy" on page 207

Lotus Notes

TCP-Tunnel



1352

Chapter 13: "Managing the TCP
Tunneling Proxy" on page 207

MMS

MMS



1755

Volume 3: Web Communication
Proxies

MS SQL
Server

TCP-Tunnel



1433

Chapter 13: "Managing the TCP
Tunneling Proxy" on page 207

MS Terminal
Services

TCP-Tunnel



3389

Chapter 13: "Managing the TCP
Tunneling Proxy" on page 207

MSN-IM

MSN-IM



1863, 6891

Volume 3: Web Communication
Proxies

MySQL

TCP-Tunnel



3306

Chapter 13: "Managing the TCP
Tunneling Proxy" on page 207

NFS

TCP-Tunnel



2049

Chapter 13: "Managing the TCP
Tunneling Proxy" on page 207

Novell
GroupWise

TCP-Tunnel



1677

Chapter 13: "Managing the TCP
Tunneling Proxy" on page 207

Novell NCP

TCP-Tunnel



524

Chapter 13: "Managing the TCP
Tunneling Proxy" on page 207

Oracle

TCP-Tunnel



1521, 1525

Chapter 13: "Managing the TCP
Tunneling Proxy" on page 207

POP3

TCP-Tunnel



110

Chapter 13: "Managing the TCP
Tunneling Proxy" on page 207

POP3S

TCP-Tunnel



995

Chapter 13: "Managing the TCP
Tunneling Proxy" on page 207

RTSP

RTSP



554

Volume 3: Web Communication
Proxies

56

Chapter 3: About Proxy Services and Proxies
Table 3–5 Proxy Name and Listeners (Continued)

Service
Name

Proxy

Destination
IP Address

Port Range

Configuration Discussed

Shell

TCP-Tunnel



514

Chapter 10: "Managing Shell
Proxies" on page 159

SMTP

TCP-Tunnel



25

Chapter 13: "Managing the TCP
Tunneling Proxy" on page 207



1080

Chapter 11: "Managing a SOCKS
Proxy" on page 167

SOCKS
SSH

TCP-Tunnel



22

Chapter 13: "Managing the TCP
Tunneling Proxy" on page 207

Sybase SQL

TCP-Tunnel



1498

Chapter 13: "Managing the TCP
Tunneling Proxy" on page 207

Telnet

Telnet



23

Chapter 10: "Managing Shell
Proxies" on page 159

VNC

TCP-Tunnel



5900

Chapter 13: "Managing the TCP
Tunneling Proxy" on page 207

XWindows

TCP-Tunnel



6000-6002

Chapter 13: "Managing the TCP
Tunneling Proxy" on page 207

Yahoo-IM

Yahoo-IM



5050, 5101

Volume 3: Web Communication
Proxies

Default
(Listens on all
unattended
ports)

TCP-Tunnel





Chapter 13: "Managing the TCP
Tunneling Proxy" on page 207

Reference: Access Log Fields
The access log has two fields: service name and service group name.


Name of the service used to intercept this connection:


x-service-name

(ELFF token) service.name (CPL token)

Note: The x-service-name field replaces the s-sitename field. The s-sitename

field can still be used for backward compatibility with squid log formats, but it
has no CPL equivalent.


Service group name:


x-service-group

(ELFF token) service.group (CPL token)

Note: See Volume 8: Access Logging, Chapter 2 and Access Log Formats,

Appendix B for detailed information about creating and editing log formats.

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Volume 2: Proxies and Proxy Services

Reference: VPM Objects
The Service Group object can be configured in the Service column of the VPM
Web Access layer.
For detailed information about VPM policy configuration, see Volume 6: The Visual
Policy Manager and Advanced Policy Tasks, Chapter 3.

Reference: CPL Policy Configuration for Service Group
The following CPL is implemented per service group:

service.group=standard reflect_ip(client)

The meaning of reflect_ip(auto) has changed in SGOS version 5.3 from
deriving the reflect client ip setting from the service attribute to inheriting the
reflect client ip setting from the global setting.

service.group=interactive client.connection.dscp(preserve)
service.group=interactive server.connection.dscp(preserve)

For detailed information about CPL policy configuration and revocation check,
see Volume 10: Content Language Policy Guide, Chapter 4.

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Chapter 4: Accelerating File Sharing

This chapter discusses file sharing optimization. File sharing uses the Common
Internet File System (CIFS) protocol.

Topics in this Chapter
This chapter includes information about the following topics:


"About the CIFS Protocol" on page 59



"About the Blue Coat CIFS Proxy Solution" on page 60



"Configuring the ProxySG CIFS Proxy" on page 62



"Reference: Equivalent CIFS Proxy CLI Commands" on page 72



"Reference: Access Log Fields" on page 73



"Reference: CPL Triggers, Properties, and Actions" on page 76

About the CIFS Protocol
The CIFS protocol is based on the Server Message Block (SMB) protocol used
for file sharing, printers, serial ports, and other communications. It is a clientserver, request-response protocol. The CIFS protocol allows computers to share
files and printers, supports authentication, and is popular in enterprises
because it supports all Microsoft operating systems, clients, and servers.
File servers make file systems and other resources (printers, mailslots, named
pipes, APIs) available to clients on the network. Clients have their own hard
disks, but they can also access shared file systems and printers on the servers.
Clients connect to servers using TCP/IP. After establishing a connection,
clients can send commands (SMBs) to the server that allows them to access
shares, open files, read and write files— the same tasks as with any file system,
but over the network.
CIFS is beneficial because it is generic and compatible with the way
applications already share data on local disks and file servers. More than one
client can access and update the same file, while not compromising file-sharing
and locking schemes. However, the challenge for an enterprise is that CIFS
communications are inefficient over low bandwidth lines or lines with high
latency, such as in enterprise branch offices. This is because CIFS transmissions
are broken into blocks of data (typically close to 64 KB). The client must stop and
wait for each block to arrive before requesting the next block. Each stop
represents time lost instead of data sent. Therefore, users attempting to access,
move, or modify documents experience substantial, work-prohibiting delays.

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Volume 2: Proxies and Proxy Services

About the Blue Coat CIFS Proxy Solution
The CIFS proxy on the ProxySG combines the benefits of the CIFS protocol with
the abilities of the ProxySG to improve performance, reduce bandwidth, and
apply basic policy checks. This solution is designed for branch office deployments
because network administrators can consolidate their Windows file servers (at the
core office) instead of spreading them across the network.

LEGEND:
A: Branch ProxySG.
B: Concentrator ProxySG.
C: File server containing objects requested by branch users.
DATA FLOW:
1: A branch client requests a file from a server at the core office.
2: If the branch proxy has the object or part of the object cached, it is served back to the client;
otherwise, the request for uncached objects is sent to the core office. With the default CIFS proxy
configuration, the ProxySG attempts to read ahead—anticipate what part(s) of a specific object might
be requested next.
3: With the default CIFS proxy configuration, byte caching compresses the data over the TCP
connection.
4: The Concentrator performs decompression and authentication tasks, accesses the content server,
and returns the content back to the branch.
5. The client receives the requested content. In addition, the anticipated content is cached so that future
requests for it can be served without requesting it from the data center.
6. Another client requests access to a file on the core server, but wants to write to the file. With the
default CIFS proxy configuration, the branch ProxySG continuously informs the client that has written
the data and that it is okay to write the next block. Simultaneously, the ProxySG sends the data over
the WAN to the file server, thus maximizing the data pipeline.
Figure 4–1

60

CIFS Proxy Traffic and Flow Diagram

Chapter 4: Accelerating File Sharing

Caching Behavior
The CIFS proxy caches the regions of files that are read or written by the client
(partial caching) and applies to both read and write file activities. Also, the
caching process respects file locking.
Note: Caching behavior can also be controlled with policy.

Authentication
The CIFS proxy supports both server and proxy authentication in the following
contexts.

Server Authentication
Permissions set by the origin content server (OCS) are always honored. Requests
to open a file are forwarded to the OCS; if the OCS rejects the client access request,
no content is served from the cache.
Note: NTLM/IWA authentication requires that the client knows what origin

server it is connecting to so it can obtain the proper credentials from the
domain controller.

Proxy Authentication
The ProxySG cannot issue a challenge to the user over CIFS, but it is able to make
use of credentials acquired by other protocols if IP surrogates are enabled.

Policy Support
The CIFS proxy supports the proxy, cache, and exception policy layers. However,
the SMB protocol can only return error numbers. Exception definitions in the
forms of strings cannot be seen by an end user. See "Reference: CPL Triggers,
Properties, and Actions" on page 76 for supported CPL triggers and actions.

Access Logging
By default, the ProxySG uses a Blue Coat-derived CIFS access log format.
date time c-ip r-ip r-port x-cifs-method x-cifs-server x-cifs-share
x-cifs-path x-cifs-orig-path x-cifs-client-bytes-read
x-cifs-server-bytes-read x-cifs-bytes-written x-cifs-file-type
s-action cs-username cs-auth-group s-ip

For a reference list and descriptions of used log fields, see "Reference: Access Log
Fields" on page 73.

WCCP Support
If WCCP is deployed for transparency, you must configure WCCP to intercept
TCP ports 139 and 445.

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Chapter 4: Accelerating File Sharing

2. Select Local Policies > Security Options.
3. Perform one of the following:


Windows XP/2003: Right-click Microsoft network client: Digitally sign
communications (always) and select Properties. A configuration dialog
appears.



Windows 2000: Right-click Digitally sign client communications (always). A
configuration dialog appears.

4. Select Disabled. Click Apply and OK.
5. Repeat for the server options:


Windows XP/2003: Right-click Microsoft network server: Digitialy sign
communications (always).



Windows 2000: Right-click Digitally sign server communications (always).

6. Close all Control Panel dialogs.
Important:

If the server is an ADS/Domain controller, you must set the
same security settings for both Administrative Tools > Domain Controller Security
Policy and Administrative Tools- > Domain Security Policy. Otherwise, you cannot
open file shares and Group Policy snap-ins on your server.

7. You must reboot the client or server to apply this configuration change.

Intercepting CIFS Services
By default (upon upgrade and on new systems), the ProxySG has CIFS services
configured for transparent connections on ports 139 and 445. Blue Coat creates
listener services on both ports because different Windows operating systems
(older versus newer) attempt to connect using 139 or 445. For example, Windows
NT and earlier only used 139, but Windows 2000 and later try both 139 and 445.
Therefore only configuring one port can potentially cause only a portion of
Windows 2000 and newer CIFS traffic to go through the proxy.

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Chapter 4: Accelerating File Sharing

Configuring the CIFS Proxy Options
The CIFS proxy options configure file reading and writing and folder
management. These options are enabled by default because they maximize the
benefits of a CIFS proxy deployment. This section describes these options and
why they might require changing based on your branch deployment.
To view/change t he CIFS proxy configuration options:

1. In the Management Console, select Configuration > Proxy Settings > CIFS Proxy.

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Volume 2: Proxies and Proxy Services



CIFS Bytes Read:



CIFS Bytes Written:



CIFS Clients:



CIFS Bandwidth Gain: The total bandwidth usage for clients (yellow) and
servers (blue), plus the percentage gain.

The total number of bytes read by CIFS clients.

The total number of bytes written by CIFS clients
(such as updating existing files on servers).
The total number of connected CIFS clients.

c. The graphs display three time metrics: the previous 60 minutes, the
previous 24 hours, and the previous 30 days. Select Duration: from the
drop-down list. Roll the mouse over any colored bar to view details.
3. (Optional) You can change the scale of the graph to display the percentage of
bar peaks to display.

Statistic URL Pages
Additional CIFS statistics pages are viewable from Management Console URLs.

Statistics
This page displays various, more granular connection and byte statistics.
https://SG_IP_address:8082/CIFS/statistics

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Chapter 4: Accelerating File Sharing

If CIFS traffic interception is occurring (the above screenshot does not represent
active traffic), the byte counters increment when a user opens a file or browses
around.
Note: The bytes to/from servers counters on the CIFS statistics page do not

include the effects of compression and byte caching over the WAN link.

Connections
This page displays specific client-to-server connection and file information and
statistics.
https://ProxySG_IP_address:8082/CIFS/connection

71

Volume 2: Proxies and Proxy Services

Click connection ID link to drill down to more details.

Reference: Equivalent CIFS Proxy CLI Commands
The Management Console procedures in this chapter have the following
equivalent CLI command roots:


To enter configuration mode for the service:
SGOS#(config) proxy-services
SGOS#(config proxy-services) create cifs service-name
SGOS#(config proxy-services) edit service-name



The following subcommands are available:
SGOS#(config service-name) add {transparent | ip_address | ip_address/
subnet-mask} {port | first_port-last_port} [intercept | bypass]
SGOS#(config service-name) attribute {adn-optimize {enable | disable}
SGOS#(config service-name) bypass {transparent | ip_address |
ip_address/subnet-mask} {port | first_port-last_port}}
SGOS#(config service-name) exit
SGOS#(config service-name) intercept {transparent | ip_address |
ip_address/subnet-mask} {port | first_port-last_port}}
SGOS#(config service-name) remove {transparent | ip_address |
ip_address/subnet-mask} {port | first_port-last_port}
SGOS#(config service-name) view

72

Chapter 4: Accelerating File Sharing



To set other configuration parameters:
SGOS#(config service-name) exit
SGOS#(config) cifs
SGOS#(config cifs)



The following subcommands are available:
SGOS#(config
SGOS#(config
SGOS#(config
SGOS#(config
SGOS#(config
SGOS#(config

cifs)
cifs)
cifs)
cifs)
cifs)
cifs)

directory-cache-time seconds
exit
read-ahead {disable | enable}
strict-directory-expiration {disable | enable}
view {configuration | statistics}
write-back (full | none}

Reference: Access Log Fields
The default Blue Coat CIFS Access Log fields are:


c-ip:



c-port:



cs-auth-group:

One group that an authenticated user belongs to. If a user
belongs to multiple groups, the group logged is determined by the Group Log
Order configuration specified in VPM. If the Group Log Order is not
specified, an arbitrary group is logged. Note that only groups referenced by
policy are considered.



cs-username: Relative username of a client authenticated to the proxy (for
example: not fully distinguished).



r-ip:



r-port:



s-action:



IP address of the CIFS client.
The CIFS client port TCP connection.

IP address from the outbound server URL.
Port from the outbound server URL, typically 139 or 445.
The logging action (or flow) being one of the following:



ALLOWED:

CIFS operation passed the policy checkpoint and was also
successful.



DENIED:



ERROR: CIFS operation resulted in an error on the server; typically
associated with NT (x-cifs-nt-error-code) or DOS error (x-cifs-doserror-code, x-cifs-dos-error-class).



FAILED:



SUCCESS:

CIFS operation failed the policy checkpoint.

CIFS operation was successful on the server but failed on the
proxy for some internal reason.

CIFS operation was successful on the server (did not go through
policy checkpoint).

s-ip:

IP address of the appliance on which the client established its
connection.

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Volume 2: Proxies and Proxy Services



Total number of bytes read by a CIFS client from
the associated resource. For OPEN/CLOSE, it is the total for that specific file. For
MOUNT/UNMOUNT, the total for all files accessed in that share. For LOGON/
LOGOFF, the total for all files accessed in that session. For CONNECT/
DISCONNECT, the total for all files accessed during that connection.



x-cifs-client-write-operations:



x-cifs-client-other-operations:



x-cifs-client-bytes-read:

Total number of client write operations for
this particular resource. The scope is the same as x-cifs-client-readoperations.

Total number of client operations that are
not reads or writes for this particular resource. The scope is the same as xcifs-client-read-operations. MOUNT/UNMOUNT might also include
operations not tied to a specific open file.
x-cifs-bytes-written:

Total number of bytes written to the associated

resource.


x-cifs-dos-error-class:

DOS error class generated by server, in

hexadecimal.


x-cifs-dos-error-code:



x-cifs-error-cod: CIFS error code generated by server. If the error code is in
NT format, it is a single hexadecimal number of the form 0xNNNNNNNN. If the
error code is in DOS format, it is two hexadecimal numbers of the form 0xNN/
0xNNNN. The first number is the DOS error class, and the second is the DOS
error code. This field is a combination of the x-cifs-nt-error-code, x-cifsdos-error-class, and x-cifs-dos-error-code.



x-cifs-fid:



x-cifs-file-size:



x-cifs-file-type: The type of file that was opened or closed. Values are file,
directory, pipe, or other. It is only valid if x-cifs-method is OPEN, CLOSE,
CLOSE_ON_UNMAP, CLOSE_ON_LOGOFF, CLOSE_ON_DISCONNECT, or
CLOSE_ON_PASSTHRU.



DOS error code generated by server, in hexadecimal.

Numeric ID representing a CIFS resource.

x-cifs-method:

Size in bytes of CIFS resource.

The method associated with the CIFS request. The list of CIFS

methods are:

74



CONNECT:



DISCONNECT:



LOGON:



LOGOFF:



LOGOFF_ON_PASSTHRU:
PASSTHRU.



LOGOFF_ON_DISCONNECT:
DISCONNECT.



MAP:



UNMAP:

For TCP-level connect from client to CIFS server.
For TCP-level connection shutdown.

For SESSION_SETUP_ANDX SMB command.
For LOGOFF_ANDX SMB command.
For removal of cached session from proxy upon
For removal of cached session from proxy upon

For TREE_CONNECT SMB command.
For TREE_DISCONNECT SMB command.

Chapter 4: Accelerating File Sharing



UNMAP_ON_LOGOFF:



UNMAP_ON_PASSTHRU:
PASSTHRU.



UNMAP_ON_DISCONNECT:
DISCONNECT.



DELETE:



DELETE_ON_CLOSE:



LIST:

For enumerating contents of a directory.



OPEN:

For opening a CIFS resource.



RENAME:



CLOSE:



CLOSE_ON_UNMAP:



CLOSE_ON_LOGOFF:



CLOSE_ON_PASSTHRU:



CLOSE_ON_DISCONNECT:
DISCONNECT.



PASSTHRU:



For removal of cached share from proxy upon LOGOFF.

For removal of cached share from proxy upon

For path-based DELETE and DELETE_DIRECTORY SMB commands.
For delete-on-close action done on a CIFS resource.

For renaming a CIFS resource.

For closing a CIFS resource.
For removal of cached file from proxy upon UNMAP.
For removal of cached file from proxy upon LOGOFF.
For removal of cached file from proxy upon PASSTHRU.
For removal of cached file from proxy upon

For connections which Blue Coat is unable to handle:



Client or server does not support NTLM 0.12 dialect.



Security signatures are enabled.



Client or server does not support Unicode characters.



The SESSION_SETUP_ANDX SMB request is malformed (with unknown
word count).



Header portion of some SMB command is malformed.



NETBIOS header is malformed.

OPEN_STATS:

Log the same fields as CLOSE for gathering time-based
activity information on open files. This occurs on a 5 minute interval if
there was activity on the file within that interval.



x-cifs-nt-error-code:



x-cifs-orig-path:



For removal of cached share from proxy upon

CIFS error code generated by server, in hexadecimal.

Original path name of resource to be renamed.

x-cifs-orig-unc-path:

UNC path of original path name of resource to be

renamed.


x-cifs-path:



x-cifs-server:



CIFS resource name as specified in the UNC path.
CIFS server as specified in the UNC path.

x-cifs-server-bytes-read: Total number of bytes read from CIFS server from

the associated resource.


x-cifs-server-operations: Total number of server operations for this
particular resource. The scope is the same as x-cifs-client-read-operations.

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Volume 2: Proxies and Proxy Services




x-cifs-share:
x-cifs-tid:

CIFS share name as specified in the UNC path.

ID representing instance of an authenticated connection to server

resource.



x-cifs-uid:

ID representing an authenticated user instance.

x-cifs-unc-path:

CIFS path of form \\server\share\path where path might

be empty.


x-client-connection-bytes:

Number of bytes sent to and received from the

client.


x-server-connection-bytes: Number of bytes sent to and received from the
server. If ADN is used for the server connection, this is the number of bytes
before ADN compression is applied.



x-server-adn-connection-bytes:

Number of bytes sent to and received from
the server-side ADN peer if ADN is used for the server connection. If ADN is
not used, this is displayed as "-".

Reference: CPL Triggers, Properties, and Actions
The following CPL applies to CIFS policy:

Triggers


attribute.=, has_attribute.=



client.address=, client.host=, client.host.has_name=



client.protocol=cifs



content_management=no



condition=



date[.utc]=, day=, hour=, minute=, month=, weekday=, year=, time=



has_client=



proxy.address=, proxy.port=, proxy.card=



raw_url=



release.*=



server_url=



service.name=cifs



tunneled=



url=cifs://:/



user.*=, group=, realm=, authenticated=

Properties and Actions:

76



action()



access_log.*(), log.*(), log_message(), notify_email(), notify_snmp()



adn.server.optimize(yes|no)

Chapter 4: Accelerating File Sharing



adn.server.optimize(byte_cache)



adn.server.optimize(compress)



adn.server.optimize.inbound(yes|no)



adn.server.optimize.outbound(yes|no)



adn.connection.dscp(DSCP_value | DSCP_name | preserve)



authenticate.*()



allow, deny, deny.*(), exception.*(), force_deny.*(),
force_exception.*()



bypass_cache()



detect_protocol(cifs), force_protocol(cifs)



limit_bandwidth(bandwidth_class)



reflect_ip()



rewrite(url), rewrite(url.host), set(url.port)



trace.*()

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Volume 2: Proxies and Proxy Services

78

Chapter 5: Managing the Domain Name Service (DNS) Proxy

This chapter discusses managing Domain Name Service (DNS) traffic through
the DNS proxy on the ProxySG (to configure the ProxySG connections to DNS
servers, see Volume 1: Getting Started). When a DNS proxy service is enabled, it
listens on port 53 for both explicit and transparent DNS domain query requests.
By default, the service is created but not enabled.
The DNS performs a lookup of the DNS cache to determine if requests can be
answered. If yes, the ProxySG responds. If not, the DNS forwards the request to
the DNS server list configured on the on the ProxySG. (To configure the DNS
server list, see Configuration > Network > DNS.)
Note: The ProxySG is not a DNS server. It does not perform zone transfers, and
recursive queries are forwarded to other name servers.

For information on managing DNS name servers, refer to Volume 1: Getting
Started.
Through policy, you can configure the list of resolved domain names (the
resolving name list) the DNS uses. The domain name in each query received by
the ProxySG is compared against the resolving name list. Upon a match, the
appliance checks the resolving list. If a domain name match is found but no IP
address was configured for the domain, the appliance sends a DNS query
response containing its own IP address. If a domain name match is found with
a corresponding IP address, that IP address is returned in a DNS query
response. All unmatched queries are sent to the name servers configured on the
ProxySG.

Topics in this Chapter
This chapter includes information about the following topics:


"Creating or Editing a DNS Proxy Service" on page 80



"Creating a Resolving Name List" on page 82

Configuring the DNS Proxy Service Options
This section describes how to change the default service options and add new
services.

Changing the Default DNS Proxy Service to Intercept All IP Addresses
on Port 53
By default (upon upgrade and on new systems), the ProxySG has an DNS
proxy service configured on port 53. The service is configured to listen to all IP
addresses, but is set in Bypass mode.

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SGOS#(config) proxy-services
SGOS#(config proxy-services) create dns service-name
SGOS#(config proxy-services) edit service-name


The following subcommands are available:
SGOS#(config service-name) add {transparent | explicit | all |
ip_address | ip_address/subnet-mask} {port | first_port-last_port}
[intercept | bypass]
SGOS#(config service-name) bypass {transparent | explicit | all |
ip_address | ip_address/subnet-mask} {port | first_port-last_port}
SGOS#(config service-name) exit
SGOS#(config service-name) intercept {transparent | explicit | all |
ip_address | ip_address/subnet-mask} {port | first_port-last_port}
SGOS#(config service-name) remove {transparent | explicit | all |
ip_address | ip_address/subnet-mask} {port | first_port-last_port}
SGOS#(config service-name) view

Creating a Resolving Name List
You can create the resolving name list that the DNS proxy uses to resolve domain
names. This procedure can only be done through policy. (For a discussion on
using the layer, refer to Volume 10: Content Policy Language Guide.)
Each name resolving list entry contains a domain-name matching pattern. The
matching rules are:
matches only test.com and nothing else.



test.com



.test.com



“.” matches all domain names.

matches test.com, www.test.com and so on.

An optional IP address can be added, which allows the DNS proxy to return any
IP address if the DNS request's name matches the domain name suffix string
(domain.name).
To create a resolving name list, create a policy, using the layer, that
contains text similar to the following:

dns.request.name=www.example.com dns.respond.a(vip)
-or
dns.request.name=.example.com dns.respond.a(vip)
-or
dns.request.name=www.example.com dns.respond.a(10.1.2.3)

Note: You can also create a resolving name list using VPM. For more information

on using the DNS-Proxy layer in VPM, refer to Volume 1: Getting Started.

82

Chapter 6: Accelerating the Microsoft Outlook Application
(Endpoint Mapper and MAPI Proxies)

This chapter discusses the Endpoint Mapper service and MAPI proxy, which
function together to intercept traffic generated by Microsoft Outlook clients
and accelerate traffic over the WAN.

Topics in this Chapter
This chapter includes information about the following topics:


"The Endpoint Mapper Proxy Service" on page 84.



"The MAPI Proxy" on page 93.

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Volume 2: Proxies and Proxy Services
Section A: The Endpoint Mapper Proxy Service

Section A: The Endpoint Mapper Proxy Service
This section discusses the Microsoft Remote Procedure Call (RPC) protocol and
describes how to configure the Endpoint Mapper proxy service on the ProxySG.

About RPC
The Microsoft RPC protocol functions across a client/server model where one
application requests a service from another application. The requesting program
is the client; the providing service is the server. RPC allows an application on one
host (the client) to request and thereby cause an application on another host (the
server) to execute an action without the requirement of explicit code. For
example: MAPI traffic.
Typically, RPC communications occur when the client contacts the Endpoint
Mapper service on that client host to determine how to contact the server. The
client provides the RPC service identifier and the Endpoint Mapper service
returns the IP and port the client uses to contact the server. Then, the client makes
a new TCP connection to that IP and port and sends its RPC request.
The challenges occur when these communications occur between branch offices
and servers located in core locations. The user experience is poor because of low
available bandwidth or high latency lines.

About the Blue Coat Endpoint Mapper Proxy Solution
The Endpoint Mapper proxy intercepts an RPC client request for a particular RPC
service. The Endpoint Mapper proxy looks up the request in its local database,
and if there is a match it replies to the client the port number the RPC service is
listening on. If it is not in the database, it forwards the request up to the server.
The server responds with the port number the service is listening on, and the
Endpoint Mapper proxy populates its internal database. It then creates a
secondary listener on that RPC port and server IP address, and responds to the
RPC client with the port number. When the RPC client connects to the service, the
Endpoint Mapper proxy secondary service intercepts the request and tunnels it.
Substantial performance increase occurs because:


The ProxySG caches server information, negating the requirement to connect
to an upstream server for repeated requests.



The ProxySG at the branch compresses RPC traffic and sends it over the TCP
connection to the core ProxySG, which decompresses the data before sending
it to the RPC server.

The Endpoint Mapper proxy can be deployed in both transparent and explicit
modes. Intercepting RPC traffic is part of the complete solution that includes the
MAPI proxy ("Section B: The MAPI Proxy" on page 93).
Note: Only Microsoft RPC version 5.0 is supported. Unsupported Microsoft RPC

version traffic is passed through the ProxySG without processing.

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Chapter 6: Accelerating the Microsoft Outlook Application (Endpoint Mapper and MAPI Proxies)
Section A: The Endpoint Mapper Proxy Service

Bypassing Endpoint Mapper Traffic
Certain scenarios might require you to change the Endpoint Mapper service from
Intercept to Bypass. For example, you need to take an Endpoint Mapper service
offline for maintenance. When an Endpoint Mapper changes from Intercept to
Bypass, the ProxySG closes not only the primary connections (such as connections
to a Microsoft Exchange server on port 135), but also the secondary connections,
which are used to intercept further RPC requests on mapped ports. The result is
fully bypassed Endpoint Mapper traffic.

Policy Support
The Endpoint Mapper proxy supports any policy that applies to TCP tunnel
connections. See "Reference: CPL Triggers, Properties, and Actions" on page 91 for
supported CPL triggers and actions.

Access Logging
Each TCP connection results in an access log entry. Both the Endpoint Mapper
proxy and secondary tunnel traffic activities are logged. The ProxySG main access
log format is used by default.
Note: If the access log for the primary connection changes to a new log, the

secondary connections are also moved to the new log.
For a reference list and descriptions of used log fields, see "Reference: Access Log
Fields" on page 90.

Configuring Endpoint Mapper Service Options
This section describes how to change the default service options and add new
services.

Configuring the Endpoint Mapper Service to Intercept All IP
Addresses on Port 135
By default (upon upgrade and on new systems), the ProxySG has an Endpoint
Mapper service configured on port 135. The service is configured to listen to all IP
addresses, but is set in Bypass mode.
The following procedure describes how to change the service to Intercept mode.
To configure the Endpoint Mapper service attributes:

1. From the Management Console, select Configuration > Services > Proxy Services.

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Chapter 6: Accelerating the Microsoft Outlook Application (Endpoint Mapper and MAPI Proxies)
Section A: The Endpoint Mapper Proxy Service

Figure 6–1

The new service displays.

Verifying the New Service
The next section references Endpoint Mapper statistics. For this example, refer to
the Active Sessions statistics, from which you can view bypassed connections.

Reviewing Endpoint Mapper Proxy Statistics
After RPC traffic begins to flow through the ProxySG, you can review the
statistics page and monitor results in various categories. The presented statistics
are representative of the client perspective.

Management Console Statistics Pages
Endpoint Mapper statistics display across multiple pages:


Statistics > Traffic Mix tab—Service and proxy data; bandwidth use and gain;
client, server, and bypassed bytes. Includes all traffic types, but you can limit
the scope to Endpoint Mapper data.



Statistics > Traffic History tab—Service and proxy data; bandwidth use and gain;

client, server, and bypassed bytes. Select Endpoint Mapper service or proxy
(related to MAPI, as described in Section B: "The MAPI Proxy" on page 93).


Statistics > Active Sessions—The Proxied Sessions

and Bypassed Connections tabs
display statistics filtered by various criteria, such as port or service type (select
Endpoint Mapper).

Statistic URL Pages
Endpoint Mapper proxy statistics pages are viewable from Management Console
URLs.

Statistics
This page displays various, more granular connection and byte statistics.
https://SG_IP_address:8082/epmapper/statistics

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Section A: The Endpoint Mapper Proxy Service

Detailed Statistics
This page displays specific client-to-server connection and file information and
statistics.
https://SG_IP_address:8082/epmapper/detailed-statistics

Reference: Equivalent Endpoint Mapper Proxy CLI Commands
The Management Console procedures in this section have the following
equivalent CLI command roots:


To enter configuration mode for the service:
SGOS#(config) proxy-services
SGOS#(config proxy-services) create endpoint-mapper service-name
SGOS#(config proxy-services) edit service-name



The following subcommands are available:
SGOS#(config service-name) add {all | ip_address | ip_address/subnetmask} {port | first_port-last_port} [intercept | bypass]
SGOS#(config service-name) attribute {adn-optimize {enable | disable}|
use-adn {enable | disable}}
SGOS#(config service-name) bypass {all | ip_address | ip_address/
subnet-mask} {port | first_port-last_port}}
SGOS#(config service-name) exit
SGOS#(config service-name) intercept {all | ip_address | ip_address/
subnet-mask} {port | first_port-last_port}}
SGOS#(config service-name) remove {all | ip_address | ip_address/
subnet-mask} {port | first_port-last_port}
SGOS#(config service-name) view

Reference: Access Log Fields
The default ProxySG Endpoint Mapper Access Log fields are:

90



date:

GMT Date in YYYY-MM-DD format.



time:

GMT time in HH:MM:SS format.



cs-bytes, sr-bytes, rs-bytes, sc-bytes: Standard ELFF format. The total
RPC byte counts in the specified direction (client-server).



cs-method:



time-taken:



c-ip:



s-action:

Request method used from client to appliance.
Time taken (in milliseconds) to process the request.

IP address of the RPC client.
The logging action (or flow) being one of the following:



ALLOWED:

Endpoint operation passed the policy checkpoint and was also
successful.



DENIED:

Endpoint operation failed the policy checkpoint.

Chapter 6: Accelerating the Microsoft Outlook Application (Endpoint Mapper and MAPI Proxies)
Section A: The Endpoint Mapper Proxy Service



FAILED:

Endpoint operation was successful on the server but failed on the
proxy for some internal reason.



TUNNELED: Traffic

was tunneled.



cs-uri-scheme:

Scheme from the log URL.



cs-host:



cs-port:



cs-username: Relative username of a client authenticated to the proxy (for
example: not fully distinguished).



s-supplier-ip:



s-supplier-name:

Hostname from the client's request URL. If URL rewrite policies are
used, this field's value is derived from the log URL.
Port used from the client to the appliance.

IP address of the upstream host (not available for a cache hit).
Hostname of the upstream host (not available for a cache

hit).


s-supplier port:

Port number of the upstream host (not available for a cache

hit).


r-supplier-ip: IP address used to contact the upstream host (not available for

a cache hit).


r-supplier-name:

Hostname used to contact the upstream host (not available

for a cache hit).


r-supplier port:

Port used to contact the upstream host (not available for a

cache hit).


sc-filter-result:

Content filtering result: Denied, Proxied, or Observed.



sc-filter-category:



s-ip: IP address of the appliance on which the client established its
connection.



s-sitename:

Content filtering category.

Service used to process the transaction.

Reference: CPL Triggers, Properties, and Actions
The following ProxySG CPL is supported in the Endpoint Mapper proxy service:


allow/deny

TCP Tunneling Triggers


Client: client.address, client.host, client.host.has_name, client protocol
(recognizes epmapper token).



Date/Time: date[.utc], day, hour, minute, month, weekday, year, time



Proxy: proxy.address, proxy.port, proxy.card



has_client



url

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Volume 2: Proxies and Proxy Services
Section A: The Endpoint Mapper Proxy Service

Properties and Actions

92



allow/deny



trace



log_message



notify_email, notify_snmp



reflect_ip



access_log



forward



socks_gateway

Chapter 6: Accelerating the Microsoft Outlook Application (Endpoint Mapper and MAPI Proxies)
Section B: The MAPI Proxy

Section B: The MAPI Proxy
This section discusses the Messaging Application Programing Interface (MAPI)
protocol and describes how to configure the services and proxy on the ProxySG.

About MAPI
MAPI is the protocol used by Microsoft Outlook (client) to communicate with
Microsoft Exchange (server), most commonly for e-mail applications. MAPI itself
is based on the Microsoft Remote Procedure Call (RPC).
Because MAPI is based on RPC, it suffers from the same performance inherent
with RPC communications. Microsoft Outlook is the most common enterprise email application. As enterprises continue to trend toward consolidating servers,
which requires more WAN deployments (branch and remote locations), e-mail
application users experience debilitating response times for not only sending and
receiving mail, but accessing message folders or changing calendar elements. This
is because MAPI RPC transmissions are broken into blocks of data (no more than
32 KB). The client must stop and wait for each block to arrive before requesting
the next block. Each stop represents time lost instead of data sent.

About the Blue Coat MAPI Solution
The MAPI proxy is similar to and actually works in conjunction with the
Endpoint Mapper proxy in that it intercepts and accelerates RPCs; however,
MAPI is always deployed transparently and does not listen on a specific port or
port range. Instead, when configured to do so, the Endpoint Mapper proxy hands
off Outlook/Exchange traffic to the MAPI proxy (but the Endpoint Mapper proxy
functionality is still required to make an RPC connection).
The MAPI proxy itself is a split proxy, which is only viable in a deployment that
consists of a branch proxy and core proxy. A split proxy employs co-operative
processing at the branch and the core to implement functionality that is not
possible in a standalone proxy. In the case of the MAPI Proxy, cooperation exists
between the branch ProxySG and the core ProxySG to reduce the number of RPCs
sent across the WAN.
The TCP connection between the branch and core proxies makes use of byte
caching for acceleration (compression).

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Section B: The MAPI Proxy

LEGEND:
A: A ProxySG 210 at a branch office; Endpoint Mapper proxy is configured on 135; MAPI proxy:
MAPI handoff, batching, and keep-alive are enabled.
B: A ProxySG 8100 appliance (concentrator) at a corporate location.
C: Wide Area Network (Internet); the ProxySG appliances communicate through a TCP tunnel.
D: Microsoft Exchange server.
PROCESS FLOW:
1: During business hours, two branch Microsoft Outlook clients send e-mails with attachments.
2: The branch proxy batches RPC messages into larger chunks.
3: With the default Endpoint Mapper proxy configuration, byte caching compresses the data
over the TCP connection.
4: The core proxy performs decompression and connects to the Exchange server for
processing to destination client.
5. Another user logs out of Microsoft Outlook at the end of the day. With keep-alive configured,
the ProxySG maintains a connection to the Exchange server and continues to queue sent
mail. When the user logs in the next morning, the ProxySG delivers the cached mail,
eliminating excessive WAN traffic increase.
Figure 6–2

MAPI Proxy Deployment and Flow Diagram

Reducing RPC Messages Across the WAN
The MAPI proxy Batching feature reduces the number of RPC messages
traversing the WAN. The branch and core appliances work together to batch
multiple RPC messages in a larger chunk, rather than sending the smaller chunks.
Also, the proxy predicts, or reads ahead, what will be requested next. When the
branch proxy receives data chunks, it begins sending the acknowledgments to the
MAPI client to satisfy that requirement of the communication process.

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Chapter 6: Accelerating the Microsoft Outlook Application (Endpoint Mapper and MAPI Proxies)
Section B: The MAPI Proxy

Maintaining Exchange Connections
The MAPI proxy Keep-Alive feature allows the ProxySG to maintain the
connection to the Exchange server after the user has logged off from Outlook.
Determined by the configurable interval, the MAPI proxy checks the Exchange
server for new mail. ADN Optimization allows the connection to remain warm so
that when the user logs on again to Outlook, the number of retrieved bytes is
lower, allowing for better performance.
The MAPI proxy remembers each user that is logged on or off. If the duration
exceeds the specified limit, or when the user logs back into the mail application,
the Keep-Alive connection is dropped.
For more information about ADN optimization, refer to Volume 5: Advanced
Networking.

Supported Servers
The MAPI proxy supports protocol optimization, byte caching, and compression
for:


MAPI 2000—Any Outlook client to Exchange Server 2000.



MAPI 2003—Outlook client 2003 and above to Exchange Server 2003.

The MAPI proxy supports byte caching, and compression for:


MAPI 2007—Outlook client 2007 to Exchange Server 2007.

Access Logging
The MAPI proxy uses a default access log format. Data includes user actions, data
lengths (bytes), and RPC data.
date, time, c-ip, c-port, r-ip, r-port, x-mapi-user, x-mapi-method,
cs-bytes, sr-bytes, rs-bytes, sc-bytes, x-mapi-sc-rpc-count, x-mapisr-rpc-count, x-mapi-rs-rpc-count, x-mapi-sc-rpc-count, s-action, csusername, cs-auth-group, s-ip

For MAPI-specific descriptions, see "Reference: Access Log Fields" .

More Conceptual Reference


"About RPC" on page 84.



Volume 5: Advanced Networking.

Configuring the ProxySG MAPI Proxy
This section contains the following sub-sections:


"This section describes how to change the default service options and add new
services." on page 85.



"Reviewing Endpoint Mapper Proxy Statistics" on page 89.

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Chapter 6: Accelerating the Microsoft Outlook Application (Endpoint Mapper and MAPI Proxies)



Interval: If Keep-Alive is enabled, how often the MAPI proxy contacts the

Exchange server to check for new messages.


Duration:

If Keep-Alive is enabled, how long the MAPI proxy maintains
the connection to the Exchange server. The connection is dropped if
the duration exceeds this value or once a user logs back in to the mail
application.



Maximum Sessions: Limits the number of occurring active keep-alive
sessions. If a new keep-alive session starts, and the specified limit is
already exceeded, the oldest keep-alive session is not dropped but no
new keep-alive sessions are created.

3. Click OK; click Apply

Reviewing MAPI Statistics
After MAPI traffic begins to flow through the ProxySG, you can review the
statistics page and monitor results in various MAPI categories. The presented
statistics are representative of the client perspective.
To review MAPI History:

1. From the Management Console, select Statistics > MAPI History.
2. View statistics:
a. Select a statistic category tab:


MAPI Clients Bytes Read: The total number of bytes read by MAPI clients.



MAPI Clients Bytes Written:

The total number of bytes written by MAPI

clients.


MAPI Clients:

The total number of connected MAPI clients.

b. The graphs display three time metrics: the previous 60 minutes, the
previous 24 hours, and the previous month. Roll the mouse over any
colored bar to view the exact metric.
3. (Optional) You can change the scale of the graph to display the percentage of
bar peaks to display.
To review MAPI Active Sessions:

1. From the Management Console, select the Statistics > Active Sessions > Proxied
Sessions tab.
2. From the first Filter drop-down list, select Proxy; from the second drop-down
list, select MAPI.
3. Click Show. The Proxied Sessions area displays MAPI statistics.

Reference: Equivalent MAPI Proxy CLI Commands
The Management Console procedures in this chapter have the following
equivalent CLI command roots:
SGOS#(config) mapi

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The following subcommands are available:
SGOS#(config mapi) handoff (enable | disable}
SGOS#(config mapi) batching {enable | disable}
SGOS#(config mapi) keep-alive {enable | disable}
SGOS#(config mapi) keep-alive interval [minutes 1-60]
SGOS#(config mapi) keep-alive duration [hours 1-72]
SGOS#(config mapi) {view | exit}

Reference: Access Log Fields
The default MAPI Access Log fields are:
"date time c-ip c-port r-ip r-port x-mapi-user "\
"x-mapi-method cs-bytes sr-bytes rs-bytes sc-bytes "\
"x-mapi-cs-rpc-count x-mapi-sr-rpc-count "\
"x-mapi-rs-rpc-count x-mapi-sc-rpc-count "\
"s-action cs-username cs-auth-group s-ip"


cs-bytes, sr-bytes, rs-bytes, sc-bytes: Standard ELFF format. The total
RPC byte counts in the specified direction (client-server).



x-mapi-method:

The end-user operation, one of:



STARTUP:

The start of a MAPI session. A single user can have more than
one active MAPI sessions for a single instance of Outlook.



SHUTDOWN:



SEND: Outlook is sending an e-mail (with or without attachments) to
Exchange and the ProxySG is batching the contents.



FETCH: Outlook is fetching an e-mail (with or without attachments) to
Exchange and the ProxySG is batching the contents.



KEEP_ALIVE_STARTUP:



KEEP_ALIVE_SHUTDOWN:



KEEP_ALIVE_NEGOTIATE: Messages were sent to query the state of the Inbox
during a keep-alive session.



KEEP_ALIVE_FETCH: An e-mail (with or without attachments) was fetched
during a keep-alive session.

The end of a MAPI session.



x-mapi-user-dn:



x-mapi-user:



s-action:

A keep-alive session started.
A keep-alive session ended.

The full user domain name gathered from the MAPI
negotiation of user credentials between Outlook and Exchange.
A shortened form of the user domain name.



ALLOWED:

The traffic was permitted through.



SUCCESS:

The traffic was successfully proxied, but was not subject to

policy.


98

DENIED:

The traffic was denied by policy.

Chapter 6: Accelerating the Microsoft Outlook Application (Endpoint Mapper and MAPI Proxies)



SERVER_ERROR: The traffic was dropped because of an error communicating

with the server.


FAILED:



BATCHED:



The traffic was dropped because of an error when handling the
messages sent by the client. Or an internal problem with the MAPI proxy.
The traffic was batched.

TUNNELED:

The traffic was tunneled to the Exchange server for one of two

reasons:


The MAPI traffic is encrypted; therefore, the ProxySG cannot batch
messages or attachments and thus cannot provide WAN optimization
benefits.



The MAPI proxy could not connect upstream through an Application
Delivery Network (ADN) tunnel.



x-cs-mapi-rpc-count:

The number of RPCs sent from the client to the proxy.



x-sr-mapi-rpc-count:

The number of RPCs sent from the proxy to the server.



x-rs-mapi-rpc-count:

The number of RPCs sent from the server to the proxy.



x-sc-mapi-rpc-count:

The number of RPCs sent from the proxy to the client.

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100

Chapter 7: Managing the File Transport Protocol (FTP) Proxy

This chapter discusses the Blue Coat implementation of proxy support for File
Transport Protocol (FTP).
The ProxySG supports two FTP modes:


Native FTP, where the client connects through the FTP proxy. Native FTP is
used when the client connects (either explicitly or transparently) through
FTP; the ProxySG then connects upstream through FTP (if necessary).



Web FTP, where the client uses an explicit HTTP connection. Web FTP is
used when a client connects in explicit mode using HTTP and accesses an
ftp:// URL. The ProxySG translates the HTTP request into an FTP request
for the origin content server (OCS), if the content is not already cached, and
then translates the FTP response with the file contents into an HTTP
response for the client.

In most environments, such as one with an inline deployment, the FTP proxy
defaults are satisfactory and do not need to be changed. If, however, your
environment has the proxy transparently intercepting only FTP control traffic,
you might need to modify the method the ProxySG uses to determine IP
addresses for FTP data connections.

Topics in this Chapter
This chapter includes information about the following topics:


"How Do I...?"



"About FTP" on page 102



"Configuring the ProxySG for Native FTP Proxy" on page 104



"Configuring FTP Connection Welcome Banners" on page 109



"Viewing FTP Statistics" on page 110

How Do I...?
To use this chapter, identify the task and click the link:
How do I...?

See...

Understand how the ProxySG manages
IP addresses?

"About FTP" on page 102

Configure IP addresses?

"Configuring IP Addresses for FTP
Control and Data Connections" on page
102

Configure native FTP?

"Configuring the ProxySG for Native
FTP Proxy" on page 104

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Volume 2: Proxies and Proxy Services

How do I...?

See...

Configure Web FTP?

Chapter 8: "Intercepting and
Optimizing HTTP Traffic" on page 111

Customize the welcome banner for the FTP
proxy?

"Configuring FTP Connection Welcome
Banners" on page 109

View FTP statistics?

"Viewing FTP Statistics" on page 110

About FTP
With Blue Coat’s implementation of FTP, you can control how the ProxySG
responds to FTP client requests. You can also control which IP addresses are used
for control and data connections to the server.
This section discusses:


"Terminology"



"Configuring IP Addresses for FTP Control and Data Connections" on page
102



"Client-Side Data Connections Mode" on page 103



"FTP Server Notes" on page 104

Terminology


FTP control and data connections: FTP uses two parallel TCP connections to
transfer a file, a control connection and a data connection.


control connections: Used for sending control information, such as user
identification and password, between two hosts.



data connections: Used to send the file contents between two hosts. By
default, the ProxySG allows both active and passive data connections.


Active (PORT) mode data connections: Data connections initiated by
an FTP server to an FTP client at the port and IP address requested by
the FTP client. This type of connection method is useful when the FTP
server can connect directly to the FTP client.



Passive (PASV) mode data connections: Data connections initiated by
an FTP client to an FTP server at the port and IP address requested by
the FTP server. This type of connection is useful in situations where an
FTP server is unable to make a direct connection to an FTP client
because the client is located behind a firewall or other similar device
where outbound connections from the client are allowed, but inbound
connections to the client are blocked.

Configuring IP Addresses for FTP Control and Data Connections
The FTP client determines whether the client-side data connection is active or
passive from the client to the ProxySG. The ProxySG determines the server-side
connections.

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By default, the ProxySG allows both active and passive data mode connections.
FTP connections are divided into client-side control and data connections and
server-side control and data connections.


Client-side control connection: The proxy always uses the IP address selected
by the client to respond to the client.



Client-side data connection: The proxy's behavior depends on the
ftp.match_client_data_ip(yes | no) property. If this property is enabled
(the default), the proxy uses the same IP address for the data connection as it
used for the client-side control connection. If the property is disabled, the
proxy uses its own IP address, choosing the address associated with the
interface used to connect back to the client.



server-side control connection: The proxy uses the IP address selected by the
reflect_ip(auto | no | client | vip | ip_address) property. By default,
this is the local proxy IP address associated with the interface used to connect
to the server.
Client IP reflection is set globally from the Configuration > Proxy Settings >
General tab. By default, the CPL reflect_ip( ) setting is auto, which uses this
global configuration value.
Note: Setting client IP address reflection for FTP affects the source address

that is used when making the outgoing control connection to the origin
server. It might also affect which address is used by the proxy for data
connections.


Server-side data connection: The proxy's behavior depends on the
ftp.match_server_data_ip(yes | no) property. If this property is enabled
(the default), the proxy uses the same IP address for the data connection as it
used for the server-side control connection. If the property is disabled, the
proxy uses its own IP address to communicate with the server, choosing the
address associated with the interface used to connect to the server.
Note: Either the reflect_ip( ) property or the reflect-client-ip

configuration must be set for the ftp.match_server_data_ip(yes) property
to be meaningful.
For information on creating and modifying policy through VPM, refer to Volume
6: The Visual Policy Manager and Advanced Policy. For information on creating and
modifying policy through CPL, refer to Volume 10: Content Policy Language Guide.
The ftp.match_server_data_ip( ) and ftp.match_client_data_ip( )
properties can only be set through CPL.

Client-Side Data Connections Mode
Administrators determine how the ProxySG responds to a request from an FTP
client for a passive mode data connection (PASV command).

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By default, some FTP clients do not open a passive mode data connection to an IP
address that is different from the IP address used for the control connection.
When PASV is disabled, some FTP clients try a PORT command automatically,
which allows requests to be received when the client doesn't allow PASV
connections to a different IP address.
Note: Some clients might display an error when PASV is disabled on the

ProxySG, requiring you to manually request PORT mode.
The FTP client software controls any messages displayed to the end user as a
result of this response from the ProxySG.

Server-Side Data Connections Mode
The ftp.server_data(auto | passive | port) property controls the type of
server-side data connection that the ProxySG opens to the server. The default of
auto means to try a passive connection first and then fall back to an active
connection if that fails.

FTP Server Notes
IIS and WS_FTP servers do not support:


Passive data connections with a source IP address that is different from the
source IP address of the control connection.



Active data connections with a destination IP address that differs from the
source IP address of the control connection.

The ftp.match_server_data_ip(no) property most likely will not work correctly
with these servers.

Notes


Internet Explorer does not support proxy authentication for native FTP.



The FTP proxy does not support customized exception text; that is, you can
use policy to deny requests, but you can't control the text sent in the error
message.

Configuring the ProxySG for Native FTP Proxy
This section discusses:

104



"Creating or Editing the FTP Service"



"Configuring the FTP Proxy" on page 107



"Configuring FTP Clients" on page 108

Chapter 7: Managing the File Transport Protocol (FTP) Proxy

Changing the Default FTP Proxy Service to Intercept
By default services are configured to accept all IP addresses in Bypass mode. The
following procedure describes how to change them to Intercept mode, and
explains other attributes within the service.
To configure the FTP proxy to intercept file sharing traffic:

1. From the Management Console, select Configuration > Services > Proxy Services.

2

3

2. Scroll the list of services to display the default FTP service line; click the +
symbol to expand the FTP services list.
3. Notice the Action for each default service (port 21) is Bypass. Select Intercept
from the drop-down list(s).
4. Click Apply.

Creating or Editing the FTP Service
An FTP service is created by default, but it is in bypass mode. The service is not
functioning until it is in intercept mode.
Note: Web FTP requires an HTTP service, not an FTP service. For information on

configuring an HTTP proxy service, see Chapter 8: "Intercepting and Optimizing
HTTP Traffic" on page 111.
To create or edit an FTP proxy service:

1. From the Management Console, select Configuration > Services > Proxy Services.
2. To edit an existing FTP proxy service, highlight the service and click Edit. To
create a new proxy service, click New.

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Chapter 7: Managing the File Transport Protocol (FTP) Proxy

Note: ADN supports passive FTP (the data connection is initiated by an

FTP client to an FTP server at the port and IP address requested by the
FTP server. Active FTP, where data connections are initiated by an FTP
server to an FTP client at the port and IP address requested by the FTP
client, is not supported.
b. The Optimize Bandwidth checkbox is selected by default if you enabled
ADN optimization during initial configuration. De-select the checkbox
if you are not configuring ADN optimization.
6. Create a new listener:
a. Click New.
b. Select a Destination IP option.
c. In the Port Range field, enter the ports on which the service should
listen. The default port for FTP is 21.
d. Select the default behavior for the service: Bypass tells the service to
ignore any traffic. Intercept configures the service to intercept the traffic
that is being proxied.
e. Click OK to close the dialog.
7. Click Apply.

Related CLI Syntax to Create/Edit an FTP Proxy Service


To enter configuration mode for the service:
SGOS#(config) proxy-services
SGOS#(config proxy-services) create ftp service-name
SGOS#(config proxy-services) edit service-name



The following subcommands are available:
SGOS#(config service-name) add {all | ip_address | ip_address/subnetmask} {port | first-port_last-port} [intercept | bypass]}
SGOS#(config service-name) attribute adn-optimize {enable | disable}|
| use-adn {enable | disable}
SGOS#(config service-name) bypass {all | ip_address | ip_address/
subnet-mask} {port | first-port_last-port}
SGOS#(config service-name) exit
SGOS#(config service-name) intercept {all | ip_address | ip_address/
subnet-mask {port | first-port_last-port}
SGOS#(config service-name) remove {all | ip_address | ip_address/
subnet-mask {port | first-port_last-port}
SGOS#(config service-name) view

Configuring the FTP Proxy
To configure the FTP proxy:

1. Select Configuration > Proxy Settings > FTP Proxy.

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2. Select Allow caching of FTP objects. The default is enabled.
3. Determine the amount of time in percentage of how long since the object was
last modified. The default is 10%.
4. Enter an amount, in hours, that the object remains in the cache before
becoming eligible for deletion. The default is 24 hours.
5. Select Allow use of PASV mode to clients. The default is enabled, allowing data
connections to be initiated by an FTP client to an FTP server at the port and IP
address requested by the FTP server.

Related CLI Syntax to Configure the FTP Proxy
SGOS#(config)
SGOS#(config)
SGOS#(config)
SGOS#(config)

ftp
ftp
ftp
ftp

login-syntax (raptor | checkpoint}
passive-mode {enable | disable}
no welcome-banner
welcome banner

SGOS#(config) caching
SGOS#(config caching) max-cache-size number8
SGOS#(config caching) ftp
SGOS#(config caching ftp) enable
SGOS#(config caching ftp) type-m-percent number
SGOS#(config caching ftp) type-n-initial number

Note: Neither proxy authentication for transparent FTP nor proxy chaining are
supported with the Checkpoint syntax.

Configuring FTP Clients
Configure an FTP client to explicitly proxy to the ProxySG. Complete the
following steps if you have a WSFtp client. Other clients vary.

108



Enable firewall.



Select USER with no logon unless you are doing proxy authentication. In that
case, select USER [email protected] fireID and specify a proxy username and
password.

Chapter 7: Managing the File Transport Protocol (FTP) Proxy

Example
The illustration demonstrates a WSFtp client configuration.

Configuring FTP Connection Welcome Banners
You can customize banners that usually describe the policies and content of the
FTP server displayed to FTP clients. Without modification, the ProxySG sends a
default banner to newly-connected FTP clients: Welcome to Blue Coat FTP.
However, you might not want users to know that a ProxySG exists on the
network. A default banner can be defined in the Management Console or the CLI,
but other banners defined for specific groups can be created in policy layers.
Note: Configurable banners are only displayable when FTP is explicitly proxied

through the ProxySG. In transparent deployments, the banner is sent to the client
when proxy authentication is required; otherwise, the banner is forwarded from
the FTP server.
To define the default FTP banner:

1. Select Configuration > Services > FTP Proxy.
2. In the Welcome Banner field, enter a line of text that is displayed on FTP clients
upon connection. If the message length spans multiple lines, the ProxySG
automatically formats the string for multiline capability.

The welcome banner text is overridden by the policy property
ftp.welcome_banner(). This is required for explicit proxy requests, when
doing proxy authentication, and also when the policy property
ftp.server_connection(deferred|immediate) is set to defer the connection.
3. Click Apply.

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Related CLI Syntax to Define the Default FTP Banner
#SGOS#(config) ftp welcome-banner "message"

Related CPL Syntax to Create Policy that Overrides the Default Banner

ftp.welcome_banner("message")

If entering text that spans more than one line, use $(crlf) for line breaks.

Viewing FTP Statistics
See Chapter 8: "Intercepting and Optimizing HTTP Traffic" on page 111 for
information about viewing the FTP statistics.

110

Chapter 8: Intercepting and Optimizing HTTP Traffic

This chapter describes how to configure the HTTP proxy to manage traffic and
accelerate performance in your environment. Whether you use the Web
browser to access productivity applications across the WAN or to access
content on the Internet, the configure the HTTP proxy to control, secure, and
accelerate all traffic that arrives on port 80.
By default, the service on port 80 is set in Bypass mode. To intercept all traffic
on port 80, see "To configure the HTTP proxy to intercept traffic:" on page 113.
The HTTP proxy is designed to control Web traffic, providing:


Security



Authentication



Virus Scanning and Patience Pages



Performance, achieved through Object Caching and Object Pipelining

Before Reading Further
Before reading this chapter you should be familiar with the concepts in the
following user guides:


"About Proxy Listeners" on page 28.



Section B: "Creating or Editing a Proxy Service" on page 37, for detailed
information on configuring proxy services.



About Authentication Modes in Volume 4: Securing the Blue Coat ProxySG
Appliance.



Configuring the Application Delivery Network in Volume 5: Advanced
Networking, if you want to optimize ADN performance on the HTTP Proxy.

Topics in this Chapter
This chapter includes information about the following topics:


Section A: "About the HTTP Proxy Service" on page 113



Section B: "Configuring the HTTP Proxy Performance" on page 119



Section C: "Caching Authenticated Data (CAD) and Caching Proxy
Authenticated Data (CPAD)" on page 141



Section D: "Viewing HTTP/FTP Statistics" on page 145



Section E: "Supporting IWA Authentication in an Explicit HTTP Proxy" on
page 149

How Do I...?
To navigate this chapter, identify the task to perform and click the link:

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Volume 2: Proxies and Proxy Services

How do I...?

See...

Intercept traffic on the HTTP Proxy?

"Changing the HTTP Proxy Service to
Intercept All IP Addresses on Port 80"
on page 113

Edit an HTTP proxy service?
Create a new HTTP Proxy service?

"Creating or Editing an HTTP Proxy
Service" on page 114

Configure the HTTP proxy to perform
transparent authentication?

See Step 4 in "Creating or Editing an
HTTP Proxy Service" on page 114

Elect to enable/disable protocol
detection?

Step 4c in "To create or edit an HTTP
proxy service:" on page 115

Configure the HTTP Proxy for object
freshness?

"Allocating Bandwidth to Refresh
Objects in Cache" on page 135
Step 4 in "To set HTTP default object
caching policy:" on page 126

Bypass the cache or not cache content
using policy?

Choose a proxy acceleration profile?

Refer to:
Volume 6: The Visual Policy Manager
and Advanced Policy
Volume 10: Content Policy Language
Guide
Use either the VPM or CPL to create
policy that allows for bypassing the
cache or for prohibiting caching
based on your needs.
"Selecting an HTTP Proxy Acceleration
Profile" on page 127

Configure the HTTP proxy to be a:
server accelerator or reverse proxy?

"Using the Portal Profile" on page 128

forward proxy?

"Using the Normal Profile" on page 128

server-side bandwidth accelerator?

"Using the Bandwidth Gain Profile" on
page 128

Fine-tune the HTTP Proxy for bandwidth
gain?

"Fine-Tuning Bandwidth Gain" on page
135
"Using Byte-Range Support" on page
136

Configure Internet Explorer to explicitly
proxy HTTP traffic?

112

"Supporting IWA Authentication in an
Explicit HTTP Proxy" on page 149

Chapter 8: Intercepting and Optimizing HTTP Traffic
Section A: About the HTTP Proxy Service

Section A: About the HTTP Proxy Service
A proxy can service requests without contacting the Origin Content Server by
retrieving content saved from a previous request made by the same client or
another client. This is called caching.
An HTTP proxy caches copies of frequently requested resources on its local hard
disk and thereby significantly reduces upstream bandwidth usage and cost, while
significantly increasing performance.
Proxy services define the ports and addresses where a ProxySG listens for
incoming requests. The ProxySG has two HTTP service listeners defined by
default — one for all IPs listening transparently on port 80 and another explicit
listener on port 8080. While you can intercept SSL traffic on either port, to enable
the ProxySG to detect the presence of SSL traffic you must enable Detect Protocol
on the service so that the SSL traffic is handed off to the SSL Proxy. For more
information on SSL proxy functionality, see "Managing the SSL Proxy" on page
177.
Further, you can create a bypass list on the ProxySG, to exclude the interception
of requests sent from specific clients to specific servers and disable caching of the
corresponding responses. The static bypass list also turns off all policy control
and acceleration for each matching request. For example, for all clients visiting
www.bluecoat.com you might exclude interception and caching of all requests,
the corresponding responses, acceleration and policy control. If you want to create
a static bypass list, used only in a transparent proxy environment, see "About the
Bypass List" on page 49.

Configuring the HTTP Proxy Service Options
This section describes how to change the default service options and add new
services.

Changing the HTTP Proxy Service to Intercept All IP Addresses on
Port 80
By default (upon upgrade and on new systems), the ProxySG has an HTTP proxy
service listener configured on port 80. The service is configured to listen to all IP
addresses, but is set in Bypass mode.
The following procedure describes how to change the service to Intercept mode.
To configure the HTTP proxy to intercept traffic:

1. From the Management Console, select Configuration > Services > Proxy Services.
2. To edit an existing HTTP proxy service, highlight the service and click Edit. To
create a new proxy service, click New.

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Chapter 8: Intercepting and Optimizing HTTP Traffic
Section A: About the HTTP Proxy Service
Table 8–1 Customizable Attributes for the HTTP Proxy Service

Attributes

Notes

Authenticate 401

Forces transparent proxy authentication
(cookie or IP, depending on the
configuration) for all requests received
on the port. This is particularly useful in
proxy chaining scenarios.
Default: Disabled

Detect Protocol

Detects the protocol being used and
helps accelerate the flow of traffic.
When detect protocol is enabled, the
TCP connection must be fully
established before the proxy contacts
the OCS. Using policy, you can enhance
granularity for protocol detection by
matching on a richer set of conditions.
Default: Disabled

Enable ADN

Secures and accelerates the delivery of
applications across the distributed
enterprise.
Enabling ADN does not guarantee that
the connections are accelerated by
ADN. For both explicit deployments
and transparent deployments, ADN
acceleration occurs only when an ADN
concentrator is present near the OCS.
For Internet traffic, an ADN
concentrator must be configured to be
an Internet gateway.
Default: Enabled

Optimize Bandwidth

Enables byte caching and compression
of traffic over the ADN network. When
ADN is configured on the ProxySG, this
setting helps reduce the amount of
bandwidth sent over ADN tunnels.
Default: Enabled

To create or edit an HTTP proxy service:

1. Review Table 8–1 on page 115, for planning information and defaults.
2. From the Management Console, select Configuration > Services > Proxy Services.
3. To edit an existing HTTP proxy service, highlight the service and click Edit. To
create a new proxy service, click New.

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Chapter 8: Intercepting and Optimizing HTTP Traffic
Section A: About the HTTP Proxy Service

b. Optimize Bandwidth: When ADN is enabled, this setting manages byte
caching and compression of traffic over the ADN network
7. (Optional when editing an existing service) Add a new listener, specifying the
port at which the ProxySG handles the traffic as HTTP. The listener can match
on a specific destination IP address or subnet and destination port or port
range, and specifies what action to perform on the traffic that matches.
To add a new listener:
a. Click New; or click Edit.
b. Select a Destination IP address option.
c. In the Port Range field, enter the ports on which the service should
listen. The default ports for HTTP are 80 and 8080.
d. Select the default behavior for the service: Bypass tells the service to
ignore any traffic. Intercept configures the service to intercept the traffic
that is being proxied.
e. Click OK to close the dialog.
8. Click Apply.

Relevant CLI Syntax to Create/Edit an HTTP Proxy Service:


To enter configuration mode for the service:
SGOS#(config) proxy-services
SGOS#(config proxy-services) create http service-name
SGOS#(config proxy-services) edit service-name



The following subcommands are available:
SGOS#(config service-name) add {transparent | explicit | all |
ip_address | ip_address/subnet-mask} {port | first_port-last_port}
[intercept | bypass]
SGOS#(config service-name) attribute {authenticate-401 {enable |
disable} | adn-optimize {enable | disable} | detect-protocol {enable |
disable} | use-adn {enable | disable}}
SGOS#(config service-name) bypass {transparent | explicit | all |
ip_address | ip_address/subnet-mask} {port | first_port-last_port}
SGOS#(config service-name) exit
SGOS#(config service-name) intercept {transparent | explicit | all |
ip_address | ip_address/subnet-mask} {port | first_port-last_port}
SGOS#(config service-name) remove {transparent | explicit | all |
ip_address | ip_address/subnet-mask} {port | first_port-last_port}
SGOS#(config service-name) view

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Section A: About the HTTP Proxy Service

Configuring IE for Web FTP with an Explicit HTTP Proxy
Web FTP is used when a client connects in explicit mode using HTTP and accesses
an ftp:// URL. The ProxySG translates the HTTP request into an FTP request for
the origin content server (OCS), if the content is not already cached. Further, it
translates the FTP response with the file contents into an HTTP response for the
client.
Since a Web FTP client uses HTTP to connect to the ProxySG, the HTTP proxy
manages this Web FTP traffic. For an explicitly configured HTTP proxy, Internet
Explorer version 6.0 users accessing FTP sites over HTTP must disable the Enable
folder view for FTP sites browser setting.
To disable Web FTP in Internet Explorer v6.0:

1. Select Tools > Internet Options.
2. Click the Advanced tab.
3. Clear the Enable folder view for FTP sites option.
4. Click OK.
For information on using FTP, see "Managing the File Transport Protocol (FTP)
Proxy" on page 101.

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Chapter 8: Intercepting and Optimizing HTTP Traffic
Section B: Configuring the HTTP Proxy Performance

Section B: Configuring the HTTP Proxy Performance
The HTTP proxy alleviates the latency in data retrieval and optimizes the delivery
of HTTP traffic through object caching and object pipelining. Caching minimizes
the transmission of data over the Internet and over the distributed enterprise,
thereby improving bandwidth use. Pipelining allows data to be pre-fetched, even
before the client requests it, and caches it to be served immediately upon request.
Hence, it directly improves response time.
For objects in cache, the ProxySG's intelligent caching mechanism maintains
object freshness. This is achieved by periodically refreshing the contents of the
cache, while maintaining the performance within your network.
The method of storing objects on disk is critical for performance and scalability.
SGOS, the operating system on the ProxySG, uses an object store system which
hashes object lookups based on the entire URL. This hashing allows access to
objects with far fewer lookups, as compared to a directory-based filesystem found
in traditional operating systems. While file systems run poorly when they are full,
a cache achieves its highest performance when it is full.
This section describes the methods you can use to configure the HTTP proxy to
optimize performance in your network.
For...

See...

Customizing the object caching policy

"Customizing the HTTP Object Caching
Policy" on page 119.

Choosing a proxy acceleration profile
that meets your specific needs

"Selecting an HTTP Proxy Acceleration
Profile" on page 127.

Fine-tuning bandwidth gain

"Fine-Tuning Bandwidth Gain" on page
135.

Customizing the HTTP Object Caching Policy
Object caching is the saving of an application object locally so that it can be served
for future requests without requiring retrieval from the OCS. Objects can, for
example, be documents, videos or images on a Web page. When objects are
cached, the only traffic that crosses the WAN are permission checks (when
required) and verification checks that ensure that the copy of the object in cache is
still fresh. By allowing objects to be shared across requests and users, object
caching greatly reduces the bandwidth required to retrieve contents and the
latency associated with user requests.
For more information on how the ProxySG executes permission checks to ensure
authentication over HTTP, see "Caching Authenticated Data (CAD) and Caching
Proxy Authenticated Data (CPAD)" on page 141.
In case of a reverse proxy, object caching reduces the load on the OCS and
improves scalability of the OCS.

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Section B: Configuring the HTTP Proxy Performance

Figure 8–1

Object Caching on the ProxySG

Before you begin customizing your HTTP Proxy policy, read the following
concepts:


"About Object Pipelining" on page 120



"About HTTP Object Types" on page 121



"About Meta Tags" on page 122



"About Tolerant HTTP Request Parsing" on page 122



"To set HTTP default object caching policy:" on page 126, to configure the
global defaults for object caching.

About Object Pipelining
A Web page is typically composed of dozens of objects. When a client requests a
Web page, all the objects must be retrieved to display the Web page. This object
retrieval process presents a delay for the end user — for example, serial retrieval
of the content would create a significant time-lag.
Although modern day browsers open multiple connections with the OCS to
retrieve objects in parallel, the ProxySG further accelerates the process with its
Object Pipelining algorithm which supports nested pipelines that are up to three
levels deep.

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The Object Pipelining algorithm allows the ProxySG to open as many
simultaneous TCP connections as the origin server allows, and retrieves objects in
parallel. The proxy also pre-fetches objects based on pipelined requests. If for
example, a pipelined HTML object has other embedded objects, the HTTP proxy
will pre-fetch those embedded objects from the Web server without a request from
the client. The objects are then ready to be delivered from the cache straight to the
user, as fast as the client can request them.
While object pipelining enhances the user experience by minimizing latency and
improving response times for first-time Web page requests, it could increase
bandwidth utilization. Therefore by default, to avoid an increase in bandwidth
utilization, object pipelining is disabled for the reverse proxy and bandwidth gain
profiles. It is enabled, by default, only on the forward proxy — Normal profile,
where enhancing the response time for clients is vital.

About HTTP Object Types
HTTP proxy categorizes HTTP objects into three types:


Type-T: The OCS specifies explicit expiration time.



Type-M: Expiration time is not specified; however, the last modified time is
specified by the OCS.



Type-N: Neither expiration nor last modified time has been specified.

The SGOS maintains the freshness for all three types of cached HTTP objects
using the Asynchronous Adaptive Refresh (AAR) algorithm. Using the AAR
algorithm the ProxySG performs freshness checks with the OCS to expunge old
content from cache and to replace it with updated content. This technique
significantly speeds subsequent requests for the same object by removing latency
as the objects in cache is refreshed asynchronous to actual user requests.
To maximize the freshness of the next access to objects in the cache, asynchronous
revalidations are performed on those objects based on their relative popularity
and the amount of time remaining before their estimated time of expiration.
Estimated expiration times vary as object content changes are observed during
such asynchronous revalidations. This happens even for type-T objects because
the expiration times of type-T objects are not always perfectly managed by
Webmasters of content servers. However, for situations where such management
can be trusted, you can configure the proxy to reduce speculative revalidation of
type-T objects. The terms revalidation and refresh mean are used
synonymously—to assess the freshness of an object by sending a conditional GET
request to the object’s OCS. Table 8–4 on page 129 lists the components that you
can configure for type-T objects.
On the ProxySG, object pipelining improves response times for first-time Web
page requests, and the AAR algorithm significantly speeds subsequent requests
by removing the latency involved in refreshing the objects.

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About Meta Tags
A meta tag is a hidden tag that placed in the of an HTML document. It
provides descriptions and keywords for search engines and can contain the
attributes — content, http-equiv, and name. Meta tags with an http-equiv
attribute are equivalent to HTTP headers.
The ProxySG does not parse HTTP meta tag headers if:


The meta tag does not appear within the first 256 bytes of the HTTP object
body. To be parsed, relevant HTTP meta tags must appear within the first 256
bytes of the HTTP object body.



The ProxyAV that is connected to your ProxySG, adds or modifies the meta
tags in its response to the ProxySG. The response body modified by the
ProxyAV is not parsed.

Planning Considerations
You can use CPL properties in the layer to control meta tag processing.
The CPL commands can be used in lieu of the check boxes for parsing meta tags
through the Management Console. For details on the meta-tags, see Step 7 in "To
set HTTP default object caching policy:" on page 126.
The following CPL commands are applicable for HTTP proxy, HTTP refresh, and
HTTP pipeline transactions:
http.response.parse_meta_tag.Cache-Control(yes|no)
http.response.parse_meta_tag.Expires(yes|no)
http.response.parse_meta_tag.Pragma.no-cache(yes|no)

VPM support to control the processing of meta tags is not available.

Related CLI Syntax to Parse Meta Tags
SGOS#(config) http [no] parse meta-tag cache-control
SGOS#(config) http [no] parse meta-tag expires
SGOS#(config) http [no] parse meta-tag pragma-no-cache

About Tolerant HTTP Request Parsing
The tolerant HTTP request parsing flag causes certain types of malformed
requests to be processed instead of being rejected.The defaults are:


Proxy Edition: The HTTP tolerant request parsing flag is not set, by default,
The ProxySG blocks malformed HTTP requests, returning a 400 Invalid Request
error.



MACH5 Edition: The HTTP tolerant request parsing flag is set by default.
Malformed HTTP requests are not blocked.

Implementation of HTTP Tolerant Request Parsing
By default, a header line that does not begin with a or space character must
consist of a header name (which contains no or space characters), followed
by a colon and an optional value.

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When the tolerant HTTP request parsing flag is either not set or is disabled, if the
header name and required details are missing, the ProxySG blocks malformed
HTTP requests and returns a 400 Invalid Request error.
With tolerant request parsing enabled, a request header name is allowed to
contain or space characters, and if the request header line does not contain
a colon, then the entire line is taken as the header name.
A header containing only one or more or space characters is considered
ambiguous. The ProxySG cannot discern if this is a blank continuation line or if it
is a blank line that signals the end of the header section. By default, an ambiguous
blank line is illegal, and an error is reported. With tolerant request parsing
enabled, an ambiguous blank line is treated as the blank line that ends the header
section.
To enable the HTTP tolerant request parsing flag:
Note: This feature is only available through the CLI.

From the (config) prompt, enter the following command to enable tolerant HTTP
request parsing (the default is disabled):
SGOS#(config) http tolerant-request-parsing

To disable HTTP tolerant request parsing:
SGOS#(config) http no tolerant-request-parsing

Configuring the Global Defaults on the HTTP Object Caching Policy
The ProxySG offers multiple configuration options that allow you to treat cached
objects in a way that best suits your business model.
The following table lists the options that you can configure.
Table 8–2 Settings for Configuring the Object Caching Policy

Settings to Configure Object Caching

Notes

Setting the maximum object cache size

Determines the maximum object size to
store in the ProxySG. All objects
retrieved that are greater than the
maximum size are delivered to the
client but are not stored in the ProxySG.
Default: 1024 MB

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Settings to Configure Object Caching

Notes

Setting the TTL for negative responses in
cache

Determines the number of minutes the
SGOS stores negative responses for
requests that could not be served to the
client.
The OCS might send a client error code
(4xx response) or a server error code
(5xx response) as a response to some
requests. If you configure the ProxySG
to cache negative responses for a
specified number of minutes, it returns
the negative response in subsequent
requests for the same page or image for
the specified length of time. The
ProxySG will not attempt to fetch the
request from the OCS. Therefore, while
server-side bandwidth is saved, you
could receive negative responses to
requests that might otherwise have
been served by accessing the OCS.
By default, the ProxySG does not cache
negative responses. It always attempts
to retrieve the object from the OCS, if it
is not already in cache.
Default: 0 minutes

Forcing freshness validation before
serving an object from cache

Verifies that each object is fresh upon
access. Enabling this setting has a
significant impact on performance
because the HTTP proxy revalidates
requested cached objects with the OCS
before serving them to the client. This
results in a negative impact on
bandwidth gain. Therefore, do not
enable this configuration unless
absolutely required.
For enabling, select the Always check
with source before serving object check
box.
Default: Disabled

Forcing HTTPS server certificate
validation

Always verifies the certificate of the
OCS for HTTPS connections.
For enabling, select the Verify server
certificate for secure connections.

Default: Disabled

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Settings to Configure Object Caching

Notes

Parsing HTTP meta tag headers

Determines how HTTP meta tag
headers are parsed in the HTML
documents. The meta tags that can be
enabled for parsing are:
• Cache-control meta tag

The sub-headers that are parsed
when this check box is selected are:
private, no-store, no-cache,
max-age, s-maxage, mustrevalidate, proxy-revalidate
• Expires meta tag

This directive parses for the date and
time after which the document
should be considered expired.
• Pragma-no-cache meta tag

This directive indicates that cached
information should not be used and
instead requests should be forwarded
to the OCS.
Default: Disabled
Allocating bandwidth on the HTTP
proxy for maintaining freshness of the
objects in cache

Allows you to specify a limit to the
amount of bandwidth the ProxySG uses
to achieve the desired freshness. Blue
Coat recommends letting the ProxySG
manage bandwidth allocation, the
default setting. For more information
see, "Allocating Bandwidth to Refresh
Objects in Cache" on page 135.
Default: Let the SG appliance manage
refresh bandwidth.

The above settings serve as defaults on the proxy. If you want a more granular
caching policy, for example— setting the TTL for an object, use Blue Coat Content
Policy Language (CPL). You can also use the VPM or CPL to bypass the cache or
to prohibit caching for a specific domain or server. Refer to Volume 10: Content
Policy Language Guide for more information.

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To set HTTP default object caching policy:

1. Review Table 8–2, for planning information and defaults.
2. From the Management Console, select Configuration > Proxy Settings > HTTP
Proxy > Policies.

3. Set the maximum object cache size. In the Do not cache objects larger than field,
enter the maximum object size to cache. The default is 1024 MB.
4. Set the negative response Time-to-Live. In the Cache negative responses for field,
enter the number of minutes SGOS stores negative responses. The default is 0.
5. Force freshness validation. To always verify that each object is fresh upon
access, select the Always check with source before serving object check box.
Enabling this setting has a significant impact on performance, do not enable
this configuration unless absolutely required.
6. Force HTTPS server certificate validation. If you communicate with an origin
content server (OCS) through HTTPS and want the OCS certificate to be
verified, be sure that Verify server certificate for secure connections is selected.
7. Disable meta-tag parsing. The default is to parse HTTP meta tag headers in
HTML documents if the MIME type of the object is text/html.
To disable meta-tag parsing, clear the check box for:


Parse cache-control meta tag

The following sub-headers are parsed when this check box is selected:
private, no-store, no-cache, max-age, s-maxage, must-revalidate,
proxy-revalidate.



Parse expires meta tag

This directive parses for the date and time after which the document
should be considered expired.

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Parse pragma-no-cache meta tag

This directive indicates that cached information should not be used and
instead requests should be forwarded to the OCS.
8. Click OK; click Apply.

Related CLI Syntax to Set HTTP Proxy Default Policy


To enter configuration mode:
SGOS#(config)caching
SGOS#(config caching)



The following subcommands are available:
SGOS#(config caching) always-verify-source
SGOS#(config caching) no always-verify-source
SGOS#(config caching) max-cache-size megabytes
SGOS#(config caching) negative-response minutes
SGOS#(config caching) refresh automatic
SGOS#(config caching) refresh no automatic
SGOS#(config caching) refresh bandwidth kbps
SGOS#(config) http parse meta-tag {cache-control | expires | pragmano-cache}
SGOS#(config)http no parse meta-tag

See Also


"Customizing the HTTP Object Caching Policy" on page 119.



Clearing the Object Cache in Volume 9: Managing the Blue Coat ProxySG
Appliance



"Selecting an HTTP Proxy Acceleration Profile" on page 127.

Selecting an HTTP Proxy Acceleration Profile
A proxy profile offers a collection of attributes that determine object caching and
object pipelining behavior. The attributes are pre-selected to meet a specific
objective — reduce response time for clients, reduce load on the OCS, reduce
server-side bandwidth usage.
Based on your needs, you can select any of the three profiles offered or you can
create a customized profile by selecting or clearing the options available within a
profile.
The available proxy profile are:


Normal (the default setting) acts as a client accelerator, and is used for
enterprise deployments.



Portal acts as a server accelerator (reverse proxy), and is used for Web hosting.



Bandwidth Gain is used for Internet Service Provider (ISP) deployments.

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Using the Normal Profile
Normal is the default profile and can be used wherever the ProxySG is used as a
normal forward proxy. This profile is typically used in enterprise environments,
where the freshness of objects is more important than controlling the use of
server-side bandwidth. The Normal profile is the profile that most follows the
HTTP standards concerning object revalidation and staleness. Additionally,
prefetching (pipelining) of embedded objects and redirects is enabled, which
reduces response time for clients.

Using the Portal Profile
When configured as a server accelerator or reverse proxy, the ProxySG improves
object response time to client requests, scalability of the origin content server
(OCS) site, and overall Web performance at the OCS. A server accelerator services
requests meant for an OCS, as if it is the OCS itself.

Using the Bandwidth Gain Profile
The Bandwidth-Gain profile is useful wherever server-side bandwidth is an
important resource. This profile is typically used in Internet Service Provider (ISP)
deployments. In such deployments, minimizing server-side bandwidth is most
important. Therefore, maintaining the freshness of an object in cache is less
important than controlling the use of server-side bandwidth. The BandwidthGain profile enables various HTTP configurations that can increase page response
times and the likelihood that stale objects are served, but it reduces the amount of
server-side bandwidth required.
The table below shows the configuration for each profile.
Table 8–3 Normal, Portal, and Bandwidth Gain Profiles

Configuration

Normal
Profile

Portal
Profile

Bandwidth
Gain

Pipeline embedded objects in client requests

Enabled

Disabled

Disabled

Pipeline embedded objects in prefetch requests

Enabled

Disabled

Disabled

Pipeline redirects for client requests

Enabled

Disabled

Disabled

Pipeline redirects for prefetch requests

Enabled

Disabled

Disabled

Cache expired objects

Enabled

Disabled

Enabled

Bandwidth Gain Mode

Disabled

Disabled

Enabled

Substitute GET for IMS (if modified since)

Disabled

Enabled

Enabled

Substitute GET for PNC (Pragma no cache)

Disabled

Enabled

Disabled

Substitute GET for HTTP 1.1 conditionals

Disabled

Enabled

Enabled

Substitute GET for IE (Internet Explorer) reload

Disabled

Enabled

Disabled

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Table 8–3 Normal, Portal, and Bandwidth Gain Profiles (Continued)

Configuration

Normal
Profile

Portal
Profile

Bandwidth
Gain

Never refresh before expiration

Disabled

Enabled

Enabled

Never serve after expiration

Disabled

Enabled

Disabled

When a ProxySG is first manufactured, it is set to a Normal profile. Depending on
your needs, you can use the Bandwidth Gain profile or the Portal profile. You can
also combine elements of all three profiles, as needed for your environment.

About HTTP Proxy Profile Configuration Components
The table below gives a definition of the customizable HTTP proxy profile
settings. Both the Management Console field and CLI (config) command text is
included.
Table 8–4 Description of Profile Configuration Components

Management Console
Check box Field

CLI (config)
Command

Definition

Pipeline embedded objects in
client request

http [no] pipeline
client requests

This configuration item applies only to HTML
responses. When this setting is enabled, and the
object associated with an embedded object
reference in the HTML is not already cached,
HTTP proxy acquires the object’s content before
the client requests the object. This improves
response time dramatically.
If this setting is disabled, HTTP proxy does not
acquire embedded objects until the client
requests them.

Pipeline redirects for client
request

http [no] pipeline
client redirects

When this setting is enabled, and the response of
a client request is one of the redirection
responses (such as 301, 302, or 307 HTTP
response code), then HTTP proxy pipelines the
object specified by the Location header of that
response, provided that the redirection location
is an HTML object. This feature improves
response time for redirected URLs.
If this setting is disabled, HTTP proxy does not
pipeline redirect responses resulting from client
requests.

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Table 8–4 Description of Profile Configuration Components (Continued)

Management Console
Check box Field

CLI (config)
Command

Definition

Pipeline embedded objects in
prefetch request

http [no] pipeline
prefetch requests

This configuration item applies only to HTML
responses resulting from pipelined objects.
When this setting is enabled, and a pipelined
object’s content is also an HTML object, and that
HTML object has embedded objects, then HTTP
proxy also pipelines those embedded objects.
This nested pipelining behavior can occur three
levels deep at most.
If this setting is disabled, the HTTP proxy does
not perform nested pipelining.

Pipeline redirects for prefetch
request

http [no] pipeline
prefetch
redirects

When this setting is enabled, HTTP proxy
pipelines the object specified by a redirect
location returned by a pipelined response.
If this setting is disabled, HTTP proxy does not
try to pipeline redirect locations resulting from a
pipelined response.

Substitute Get for IMS

http [no]
substitute ifmodified-since

If the time specified by the If-ModifiedSince: header in the client’s conditional request
is greater than the last modified time of the
object in the cache, it is a strong indication that
the copy in the cache is stale. If so, HTTP proxy
does a conditional GET to the OCS, based on the
last modified time of the cached object.
To control this aspect of the SGOS treatment of
the If-Modified-Since: header, disable the
Substitute Get for IMS setting.
When this setting is disabled, a client time
condition greater than the last modified time of
the object in the cache does not trigger
revalidation of the object.
Note: All objects do not have a last-modified
time specified by the OCS.

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Table 8–4 Description of Profile Configuration Components (Continued)

Management Console
Check box Field

CLI (config)
Command

Definition

Substitute Get for HTTP 1.1
conditionals

http [no]
substitute
conditional

HTTP 1.1 provides additional controls to the
client over the behavior of caches concerning the
staleness of the object. Depending on various
Cache-Control: headers, the ProxySG can be
forced to consult the OCS before serving the
object from the cache. For more information
about the behavior of various Cache-Control:
header values, refer to RFC 2616.
If the Substitute Get for HTTP 1.1 Conditionals
setting is enabled, HTTP proxy ignores the
following Cache-Control: conditions from the
client request:
• "max-stale" [ "=" delta-seconds ]
• "max-age" "=" delta-seconds
• "min-fresh" "=" delta-seconds
• "must-revalidate"
• "proxy-revalidate"

Substitute Get for PNC

http [no]
substitute pragmano-cache

Typically, if a client sends an HTTP GET request
with a Pragma: no-cache or Cache-Control:
no-cache header (for convenience, both are
hereby referred to as PNC), a cache must consult
the OCS before serving the content. This means
that HTTP proxy always re-fetches the entire
object from the OCS, even if the cached copy of
the object is fresh. Because of this, PNC requests
can degrade proxy performance and increase
server-side bandwidth utilization. However, if
the Substitute Get for PNC setting is enabled,
then the PNC header from the client request is
ignored (HTTP proxy treats the request as if the
PNC header is not present at all).

Substitute Get for IE reload

http [no]
substitute iereload

Some versions of Internet Explorer issue the
Accept: */* header instead of the Pragma:
no-cache header when you click Refresh. When
an Accept header has only the */* value, HTTP
proxy treats it as a PNC header if it is a type-N
object. You can control this behavior of HTTP
proxy with the Substitute GET for IE Reload
setting. When this setting is enabled, the HTTP
proxy ignores the PNC interpretation of the
Accept: */* header.

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Table 8–4 Description of Profile Configuration Components (Continued)

Management Console
Check box Field

CLI (config)
Command

Definition

Never refresh before
expiration

http [no] strictexpiration refresh

Applies only to cached type-T objects. For
information on HTTP object types, see "About
HTTP Object Types" on page 121.
When this setting is enabled, SGOS does not
asynchronously revalidate such objects before
their specified expiration time.
When this setting is disabled, such objects, if
they have sufficient relative popularity, can be
asynchronously revalidated and can, after a
sufficient number of observations of changes,
have their estimates of expiration time adjusted
accordingly.

Never serve after expiration

http [no] strictexpiration serve

Applies only to cached type-T objects.
If this setting is enabled, an object is
synchronously revalidated before being served
to a client, if the client accesses the object after its
expiration time.
If this setting is disabled, the object is served to
the client and, depending on its relative
popularity, may be asynchronously revalidated
before it is accessed again.

Cache expired objects

http [no] cache
expired

Applies only to type-T objects.
When this setting is enabled, type-T objects that
are already expired at the time of acquisition is
cached (if all other conditions make the object
cacheable).
When this setting is disabled, already expired
type-T objects become non-cacheable at the time
of acquisition.

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Table 8–4 Description of Profile Configuration Components (Continued)

Management Console
Check box Field

CLI (config)
Command

Definition

Enable Bandwidth Gain Mode

bandwidth-gain
{disable | enable}

This setting controls both HTTP-object
acquisition after client-side abandonment and
AAR (asynchronous adaptive refresh)
revalidation frequency.
• HTTP-Object Acquisition
When Bandwidth Gain mode is enabled, if a
client requesting a given object abandons its
request, then HTTP proxy immediately
abandons the acquisition of the object from
the OCS, if such an acquisition is still in
progress. When bandwidth gain mode is
disabled, the HTTP proxy continues to
acquire the object from the OCS for possible
future requests for that object.
• AAR Revalidation Frequency
Under enabled bandwidth gain mode, objects
that are asynchronously refreshable are
revalidated at most twice during their
estimated time of freshness. With bandwidth
gain mode disabled, they are revalidated at
most three times. Not all asynchronously
refreshable objects are guaranteed to be
revalidated.

Configuring the HTTP Proxy Profile
You can configure the profile using any of the components discussed above.
To configure the HTTP proxy profile:

1. Review the description of the components for each profile, see Table 8–4 on
page 129.
2. From the Management Console, select Configuration > Proxy Settings > HTTP
Proxy > Acceleration Profile.
The Acceleration Profile tab displays (Normal is the default profile). Text
appears at the bottom of this tab indicating which profile is selected. If you
have a customized profile, this text does not appear.

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Fine-Tuning Bandwidth Gain
In addition to the components related to top-level profiles, other configurable
items affect bandwidth gain. You can set the top-level profile (see "Selecting an
HTTP Proxy Acceleration Profile" on page 127) and adjust the following
configuration items to fine tune the ProxySG for your environment:


Allocating bandwidth to refresh objects in cache



Using Byte-range support



Enabling the Revalidate pragma-no-cache(PNC)

Allocating Bandwidth to Refresh Objects in Cache
The ProxySG uses as much bandwidth as necessary for refreshing content on
frequently accessed cached objects and for maintaining their freshness. The
amount of bandwidth used varies depending on client demands.
The Refresh bandwidth option refers to server-side bandwidth used for all forms of
asynchronous refresh activity. If you determine that the ProxySG is using too
much bandwidth, you can specify a limit to the amount of bandwidth the
ProxySG uses to achieve the desired freshness. Before making adjustments,
review the logged statistics and examine the current bandwidth used as displayed
in the Refresh bandwidth field. It is not unusual for bandwidth usage to spike
occasionally, depending on access patterns at the time.
To limit the refresh bandwidth to a specified amount, you must disable automatic
management of the bandwidth and explicitly set a bandwidth limit. Setting the
refresh bandwidth amount too low can lower the estimated freshness of objects in
the cache. If you set the refresh bandwidth amount to zero, the ProxySG does not
do active refresh at all.
If the refresh bandwidth configuration remains at the recommended default—Let
the SG appliance manage refresh bandwidth (recommended) in the Management
Console or SGOS#(config caching) refresh automatic in the CLI—then the

appliance uses whatever bandwidth is available in its efforts to maintain 99.9%
estimated freshness of the next access.

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To set refresh bandwidth:

1. From the Management Console, select Configuration > Proxy Settings > HTTP
Proxy > Freshness.

The Refresh bandwidth field displays the refresh bandwidth options. The
default setting is to allow the ProxySG to manage refresh bandwidth
automatically.
Important:

Blue Coat strongly recommends that you not change the setting
from the default.

2. Do one of the following:


To turn off automatic bandwidth refresh, select Limit refresh bandwidth to
(not recommended). Enter a new value into the kilobits/sec field, if
necessary.



To return the appliance to automatic bandwidth refresh,
Appliance manage refresh bandwidth (recommended).

select Let the SG

3. Click OK; click Apply.

Relevant CLI Syntax to Set Refresh Bandwidth
SGOS#(config) caching


The following subcommands are available:
SGOS#(config caching) refresh automatic
SGOS#(config caching) refresh bandwidth kbps

Using Byte-Range Support
Byte-range support is an HTTP feature that allows a client to use the Range: HTTP
header for requesting a portion of an object rather than the whole object. The
HTTP proxy supports byte-range support and it is enabled by default.

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When Byte-Range Support is Disabled
If byte-range support is disabled, HTTP treats all byte-range requests as noncacheable. Such requests are never served from the cache, even if the object exists
in the cache. The client’s request is sent unaltered to the OCS and the response is
not cached. Thus, a byte-range request has no effect on the cache if byte-range
support is disabled.

When Byte-Range Support is Enabled
If the object is already in cache, the ProxySG serves the byte-range request from
the cache itself. However, if the client’s request contains a PNC header, the
ProxySG always bypasses the cache and serves the request from the OCS.
If the object is not in cache, the ProxySG always attempts to minimize delay for
the client.


If the byte-range requested is near the beginning of the object, that is the start
byte of the request is within 0 to 14336 bytes, then the ProxySG fetches the
entire object from the OCS and caches it. However, the client is served the
requested byte-range only.



If the byte-range requested is not near the beginning of the object, that is the
start byte of the request is greater than 14336 bytes, then the ProxySG fetches
only the requested byte-range from the OCS, and serves it to the client. The
response is not cached.
Note: The HTTP proxy never caches partial objects, even if byte-range

support is enabled.
Since the ProxySG never caches partial objects, bandwidth gain is significantly
affected when byte-range requests are used heavily. If, for example, several clients
request an object where the start byte offset is greater than 14336 bytes, the object
is never cached. The ProxySG fetches the same object from the OCS for each
client, thereby causing negative bandwidth gain.
Further, download managers like NetAnts® typically use byte-range requests
with PNC headers. To improve bandwidth gain by serving such requests from
cache, enable the revalidate pragma-no-cache option along with byte-range support.
See "Enabling Revalidate Pragma-No-Cache" on page 138.

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To configure byte-range support:
Note: Enabling or disabling byte-range support can only be configured through

the CLI.
To enable or disable byte-range support, enter one of the following commands at
the (config) command prompt:
SGOS#(config) http byte-ranges
-orSGOS#(config) http no byte-ranges

Enabling Revalidate Pragma-No-Cache
The pragma-no-cache (PNC) header in a client’s request causes the HTTP proxy to
re-fetch the entire object from the OCS, even if the cached copy of the object is
fresh. This roundtrip for PNC requests can degrade proxy performance and
increase server-side bandwidth utilization.
While the Substitute Get for PNC configuration completely ignores PNC in client
requests and potentially serves stale content, the revalidate-pragma-no-cache
setting allows you to selectively implement PNC.
When the revalidate-pragma-no-cache setting is enabled, a client’s nonconditional PNC-GET request results in a conditional GET request sent to the
OCS if the object is already in cache. The revalidate-pragma-no-cache request
allows the OCS to return the 304 Not Modified response, if the content in cache is
still fresh. Thereby, the server-side bandwidth consumed is lesser as the full
content is not retrieved again from the OCS.
By default, the revalidate PNC configuration is disabled and is not affected by
changes in the top-level profile. When the Substitute Get for PNC configuration is
enabled (see Table 8–4, "Description of Profile Configuration Components" on
page 129 for details), the revalidate PNC configuration has no effect.
To configure the revalidate PNC setting:
Note: The revalidate pragma-no-cache setting can only be configured through
the CLI.

To enable or disable the revalidate PNC setting, enter one of the following
commands at the (config) command prompt:
SGOS#(config) http revalidate-pragma-no-cache
-orSGOS#(config) http no revalidate-pragma-no-cache

Interpreting Negative Bandwidth Gain Statistics
Bandwidth gain represents the overall bandwidth benefit achieved by object and
byte caching, compression, protocol optimization, and object caching.
Occasionally, you might notice negative bandwidth gain when using the
bandwidth gain profile. This negative bandwidth gain is observed because the

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client-side cumulative bytes of traffic is lower than the server-side cumulative
bytes of traffic for a given period of time. It is represented as a unit-less
multiplication factor and is computed by the ratio:
client bytes / server bytes

Some factors that contribute to negative bandwidth gain are:


Abandoned downloads (delete_on_abandonment (no))
When a client cancels a download, the ProxySG continues to download the
requested file to cache it for future requests. Since the client has cancelled the
download, server-side traffic persists while the client-side traffic is halted.
This continued flow of traffic on the server-side causes negative bandwidth
gain.
Further with (delete_on_abandonment (yes)), when a client cancels a
download, the ProxySG terminates the connection and stops sending traffic to
the client. However, the server may have sent additional traffic to the ProxySG
before it received the TCP RESET from the ProxySG. This surplus also causes
negative bandwidth gain.



Refreshing of the cache
Bandwidth used to refresh contents in the cache contributes to server-side
traffic. Since this traffic is not sent to the client until requested, it might cause
negative bandwidth gain.



Byte-range downloads
When download managers use an open-ended byte-range, such as Range:
bytes 10000- , and reset the connection after downloading the requested byterange. The packets received by the ProxySG from the server are greater than
those served to the client, causing negative bandwidth gain.



Download of uncompressed content
If the ProxySG downloads uncompressed content, but compresses it before
serving the content to the client, server-side traffic will be greater than clientside traffic. This scenario is typical in a reverse proxy deployment, where the
server offloads the task of gzipping the content to the ProxySG.



Reduced client-side throughput
In the short term, you will notice negative bandwidth gain if the client-side
throughput is lower than the server-side throughput. If, for example, the
ProxySG takes 5 minutes to download a 100 Mb file and takes 10 minutes to
serve the file to the client. The ProxySG will reflect negative bandwidth gain
for the first 5 minutes.

To view bandwidth usage and bandwidth gain statistics on the HTTP proxy, click
Statistics > Traffic History tab. Select the HTTP proxy service to view statistics over
the last hour, day, week, month, and year. Refer to the Statistics chapter in Volume
9: Managing the Blue Coat ProxySG Appliance, for information on the graphs.

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Related CLI Syntax to Configure HTTP
The following commands allow you to manage settings for an HTTP proxy.
Use the command below to enter the configuration mode.
SGOS# conf t


The following subcommands are available:
SGOS#(config) http [no] add-header client-ip
SGOS#(config) http [no] add-header front-end-https
SGOS#(config) http [no] add-header via
SGOS#(config) http [no] add-header x-forwarded-for
SGOS#(config) http [no] byte-ranges
SGOS#(config) http [no] cache authenticated-data
SGOS#(config) http [no] cache expired
SGOS#(config) http [no] cache personal-pages
SGOS#(config) http [no] force-ntlm
SGOS#(config) http ftp-proxy-url root-dir
SGOS#(config) http ftp-proxy-url user-dir
SGOS#(config) http [no] parse meta-tag {cache-control | expires |
pragma-no-cache}
SGOS#(config) http [no] persistent client
SGOS#(config) http [no] persistent server
SGOS#(config) http [no] persistent-timeout client num_seconds
SGOS#(config) http [no] persistent-timeout server num_seconds
SGOS#(config) http [no] pipeline client {requests | redirects}
SGOS#(config) http [no] pipeline prefetch {requests | redirects}
SGOS#(config) http [no] proprietary-headers bluecoat
SGOS#(config) http receive-timeout client num_seconds
SGOS#(config) http receive-timeout refresh num_seconds
SGOS#(config) http receive-timeout server num_seconds
SGOS#(config) http [no] revalidate-pragma-no-cache
SGOS#(config) http [no] strict-expiration refresh
SGOS#(config) http [no] strict-expiration serve
SGOS#(config) http [no] strip-from-header
SGOS#(config) http [no] substitute conditional
SGOS#(config) http [no] substitute ie-reload
SGOS#(config)
SGOS#(config)
SGOS#(config)
SGOS#(config)
SGOS#(config)
SGOS#(config)
SGOS#(config)
SGOS#(config)

http
http
http
http
http
http
http
http

[no] substitute if-modified-since
[no] substitute pragma-no-cache
[no] tolerant-request-parsing
upload-with-pasv disable
upload-with-pasv enable
version {1.0 | 1.1}
[no] www-redirect
[no] xp-rewrite-redirect

Note: For detailed information about using these commands, refer to Volume
11: Command Line Interface Reference.

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Section C: Caching Authenticated Data (CAD) and Caching Proxy Authenticated Data (CPAD)

Section C: Caching Authenticated Data (CAD) and Caching Proxy
Authenticated Data (CPAD)
This section describes how the ProxySG caches authenticated content over HTTP.
Authentication over HTTP allows a user to prove their identity to a server or an
upstream proxy to gain access to a resource.
The ProxySG uses CAD and CPAD to facilitate object caching at the edge and to
help validate user credentials. Object caching in the ProxySG allows for lesser
bandwidth usage and faster response times between the client and the server or
proxy.
The deployment of the ProxySG determines whether it performs CAD or CPAD:


When the Origin Content Server (OCS) performs authentication, the ProxySG
performs CAD.



When the upstream HTTP Proxy performs authentication, the downstream
HTTP proxy or ProxySG executes CPAD.

About Caching Authenticated Data (CAD)
In the CAD scenario, when a user requests a resource that needs authentication,
the OCS sends an HTTP 401 error response to the user. The HTTP 401 response
also contains information on the authentication schemes that the OCS supports.
To prove their identity to the OCS, the user resubmits the initial request along
with the authentication details.

Figure 8–2

CAD: 200 response from the Origin Content Server.

The OCS then sends back one of the following responses:


HTTP 200 response status, authentication is accepted. The user receives the
requested resource.

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HTTP 403 response status, user is not allowed to view the requested resource.
The user is authenticated but is not authorized to receive the content, hence
the user receives an error message. See Figure 8-2.

When another user accesses the same URL, the ProxySG authenticates the user
with the OCS and verifies the freshness of the content using the Get If Modified
Since request. If the user is authorized and the content has not been modified, the
OCS returns an HTTP 304 response message to the ProxySG. The ProxySG then
serves the content from cache.
If the content has been modified, the OCS returns the HTTP 200 response along
with the modified content.

Figure 8–3

CAD: 403 and 304 response codes from the OCS

Note: CAD is applicable only for pure HTTP authentication — the ProxySG

caches authenticated data only when the OCS includes the www-Authenticate
response code in the 401 response header. If, for example, the client accesses an
OCS that uses forms-based authentication, the ProxySG does not perform CAD.

About Caching Proxy Authenticated Data (CPAD)
The CPAD deployment uses two ProxySG appliances — a local proxy and a
gateway proxy. Figure 8–4 on page 143 below depicts the ProxySG appliances in a
CPAD deployment.
When the user requests a resource, ProxySG1 forwards the request to ProxySG2.
ProxySG2 issues the authentication challenge back to the user (a 407 response
instead of the 401 response that the OCS serves). Upon successful authentication,
ProxySG2 forwards the request to the OCS and the resource is served to the user.

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Section C: Caching Authenticated Data (CAD) and Caching Proxy Authenticated Data (CPAD)

Figure 8–4

CPAD: 200 response from ProxySG 2

In Figure 8–5, ProxySG1 caches proxy authenticated data and ProxySG2 performs
authentication (instead of the OCS).

Figure 8–5

CPAD: 407 and 304 responses in a CPAD deployment

For subsequent users who access the same URL, see Figure 8-4, ProxySG1 forwards
all requests to ProxySG2 with the Get If Modified Since request.
ProxySG2

issues the authentication challenge and provides one of the following
responses:

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144



HTTP 200 response status, the user is allowed access to the requested resource
but the content has changed.



HTTP 304 response status, the user is authorized and the content can be
served from the cache.



HTTP 403 response status, the user is not authorized to view the requested
resource.



HTTP 407 response status, the user provided invalid credentials.

Chapter 8: Intercepting and Optimizing HTTP Traffic
Section D: Viewing HTTP/FTP Statistics

Section D: Viewing HTTP/FTP Statistics
HTTP/FTP History Statistics
The HTTP/FTP History tabs display bar graphs that illustrate the last 60 minutes, 24
hours, and 30 days for the number of objects served, bytes served, active clients,
and client and server compression gain statistics associated with the HTTP,
HTTPS, and FTP protocols. The overall client and server compression-gain
statistics are displayed under System Usage.
Note: You can view current HTTP statistics through the CLI using the show httpstats

command.

Viewing the Number of HTTP/HTTPS/FTP Objects Served
The HTTP/HTTPS/FTP Objects tab illustrates the device activity over the last 60
minutes, 24 hours, and 30 days. These charts illustrate the total number of objects
served from either the cache or from the Web.
The maximum number of objects that can be stored on a ProxySG is affected by a
number of factors, including the SGOS version it is running and the hardware
platform series.
To view the number of HTTP/HTTPS/FTP objects served:

1. From the Management Console, select Statistics > Protocol Details > HTTP/FTP
History > HTTP/HTTPS/FTP Objects.
2. Select the Duration: from the drop-down list.

3. (Optional) To set the graph scale to a different value, select a value from the
Graph scale should drop-down list.

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Viewing the Number of HTTP/HTTPS/FTP Bytes Served
The Bytes tab shows the sum total of the number of bytes served from the device
over the last 60 minutes, 24 hours, and 30 days. The chart shows the total number
of bytes for objects served by the device, including both cache hits and cache
misses.
To view the number of HTTP/HTTPS/FTP bytes served:

1. From the Management Console, select Statistics > Protocol Details > HTTP/FTP
History > HTTP/HTTPS/FTP Bytes.
2. Select the Duration: from the drop-down list.

3. (Optional) To set the graph scale to a different value, select a value from the
Graph scale should drop-down list.

Viewing Active Client Connections
The HTTP/HTTPS/FTP Clients tab shows the maximum number of clients with
requests processed over the last 60 minutes, 24 hours, and 30 days. This does not
include idle client connections (connections that are open but that have not made
a request). These charts allow you to monitor the maximum number of active
clients accessing the ProxySG at any one time. In conjunction with the HTTP/
HTTPS/FTP Objects and HTTP/HTTPS/FTP Bytes tabs, you can determine the
number of clients supported based on load, or load requirements for your site
based on a specific number of clients.
To view the number of active clients:

1. From the Management Console select Statistics > Protocol Details > HTTP/FTP
History > HTTP/HTTPS/FTP Clients.
2. Select the Duration: from the drop-down list.

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Section D: Viewing HTTP/FTP Statistics

3. (Optional) To set the graph scale to a different value, select a value from the
Graph scale should drop-down list.

Viewing HTTP/HTTPS/FTP Client and Server Compression Gain
Statistics
Under HTTP/FTP History, you can view HTTP/FTP client and server
compression-gain statistics for the ProxySG over the last 60 minutes, 24 hours,
and 30 days in the Client Comp. Gain and the Server Comp. Gain tabs. Overall
client and server compression-gain statistics are displayed under System Usage.
These statistics are not available through the CLI.
The green display on the bar graph represents uncompressed data; the blue
display represents compressed data. Hover your cursor over the graph to see the
compressed gain data.
To view HTTP/FTP client compressed gain statistics:

1. From the Management Console, select Statistics > Protocol Details > HTTP/FTP
History > Client Comp. Gain.
2. Select the Duration: from the drop-down list.

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3. (Optional) To set the graph scale to a different value, select a value from the
Graph scale should drop-down list.
To view HTTP/FTP server compressed gain statistics:

1. From the Management Console, select Statistics > Protocol Details > HTTP/FTP
History > Server Comp. Gain.
2. Select the Duration: from the drop-down list.

3. (Optional) To set the graph scale to a different value, select a value from the
Graph scale should drop-down list.

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Chapter 8: Intercepting and Optimizing HTTP Traffic
Section E: Supporting IWA Authentication in an Explicit HTTP Proxy

Section E: Supporting IWA Authentication in an Explicit HTTP Proxy
Internet Explorer does not allow IWA authentication through a ProxySG when
explicitly proxied. To facilitate this authentication, Blue Coat added a ProxySupport: Session-based-authentication header. By default, when the ProxySG
receives a 401 authentication challenge from upstream, it sends the ProxySupport: Session-based-authentication header in response.
The Proxy-Support header is not supported if:



you are using an older browser (Refer to the Release Notes for supported
browser versions).
both the ProxySG and the OCS perform IWA authentication.

In either case, Blue Coat recommends that you disable the header and enable
To enable this setting through policy, you must
create a Web Access Layer in the Visual Policy Manager, see Volume 6: The Visual
Policy Manager and Advanced Policy. The Force IWA for Server Authentication action,
converts the 401-type server authentication challenge to a 407-type proxy
authentication challenge that Internet Explorer supports. The ProxySG also
converts the resulting Proxy-Authentication headers in client requests to standard
server authorization headers, which allows an IWA authentication challenge to
pass through when Internet Explorer is explicitly proxied through the appliance.
Force IWA for Server Authentication.

Disabling the Proxy-Support Header
The Proxy-Support header is sent by default when an explicitly configured
ProxySG receives a 401 authentication challenge from upstream.
The header modification policy allows you to suppress or modify the ProxySupport custom header, and prevents the ProxySG from sending this default
header. Use either the Visual Policy Manager (VPM) or CPL to disable the header
through policy. For complete information on using VPM, refer to Volume 6: The
Visual Policy Manager and Advanced Policy.
Note: To suppress the Proxy-Support header globally, use the http force-ntlm

command to change the option. To suppress the header only in certain situations,
continue with the procedures below.
To suppress the proxy-support header through VPM:

To suppress the header using VPM, create a new Web Access Layer. Then:
1. Right click in the Action field to see the drop-down list; select Set.
2. Click New to see the drop-down list; select Control Response Header.

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3a
3b
3c
3d

3. Fill in the fields as follows:
a. Name: Enter a meaningful name.
b. Show: Select Custom from the drop-down list.
c. Header Name: Enter Proxy-Support.
d. Verify Suppress is selected.
4. Click OK; click Apply.
To suppress the proxy-support header through CPL:

Use CPL to define the Proxy-Support custom header object and to specify what
action to take. The example below uses Proxy-Support as the action name, but
you can choose any name meaningful to you. The result of this action is to
suppress the Proxy-Support header

action.Proxy-Support(yes)
define action Proxy-Support
delete(response.x_header.Proxy-Support)
end action Proxy-Support

150

Chapter 9: Configuing and Managing an HTTPS Reverse
Proxy Service

This chapter describes the Blue Coat HTTPS Reverse Proxy implementation,
which:


Combines hardware-based SSL acceleration with full caching functionality.



Establishes and services incoming SSL sessions.



Provides SSL v2.0, SSL v3.0, and TLSv1 protocol support.

Creating an HTTPS reverse proxy is unlike other proxies in that a number of
preliminary steps are required before you can use the proxy.
Preliminary steps include:


Creating or importing a keyring. (Refer to Volume 4: Securing the Blue Coat
ProxySG Appliance for information on creating or importing a keyring.)



(If necessary) Creating Certificate Signing Requests (CSRs) that can be sent
to Certificate Signing Authorities (CAs).



Importing server certificates issued by CA authorities for external use and
associate them with the keyring. (Refer to Volume 4: Securing the Blue Coat
ProxySG Appliance.)
-or-



Creating certificates for internal use and associate them with the keyring.



(Optional, if using server certificates from CAs) Importing Certificate
Revocation Lists (CRLs) so the ProxySG can verify that certificates are still
valid.

When these steps are complete, you can configure the HTTPS Reverse Proxy
service.
A common scenario in using HTTPS Reverse Proxy, which connects the client
to the ProxySG, is in conjunction with HTTPS origination, which is used to
connect the to the origin content server (OCS). For more information on this
option, see Section B: "Configuring HTTP or HTTPS Origination to the Origin
Content Server" on page 156.

Topics in this Chapter
This chapter includes information about the following topics:


"Configuring the HTTPS Reverse Proxy" on page 152



"Configuring HTTP or HTTPS Origination to the Origin Content Server" on
page 156

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Note: The configuration-passwords-key keyring that shipped with the
ProxySG does not contain a certificate.

The appliance-key keyring does contain a certificate if you have Internet
connectivity, but it cannot be used for purposes other than appliance
authentication. For information about appliance authentication, see
Chapter 2 of Volume 5: Advanced Networking.
c. CA Cert List: Use the drop-down list to select any already created list
that is on the system.
d. SSL Versions: Use the drop-down list to select the version to use for this
service. The default is SSL v2/v3 and TLS v1.
e. Verify Client (Used with the Forward Client Certificate option.). Selecting
this checkbox enables the Forward Client Certificate and puts the
extracted client certificate information into the Client-Cert header
that is included in the request when it is forwarded to the origin
content server. The header contains the certificate serial number,
subject, validity dates, and issuer (all as name=value pairs). The actual
certificate itself is not forwarded.
f.

Forward Client Cert:

(Should be used with the Verify Client option.)
Selecting this option puts the extracted client certificate information
into a header that is included in the request when it is forwarded to the
OCS.

5. Configure ADN options:
a. Enable ADN: Controls whether ADN is enabled for a specific service.
Enabling ADN does not guarantee the connections are accelerated by
ADN. The actual enable decision is determined by ADN routing (for
explicit deployment) and network setup (for transparent deployment)
b. The Optimize Bandwidth option is selected by default if you enabled
ADN optimization during initial configuration. Clear this option if
you are not configuring ADN optimization.
6. Add a new listener:
a. Click New to add a new listener to the HTTPS Reverse Proxy; click Edit
to change the current settings.
b. Select a Destination IP address option from the drop-down list.
c. Identify the port to which this service to listens.
d. Select the default behavior for the service: Bypass tells the service to
ignore any traffic. Intercept configures the service to intercept the traffic
that is being proxied.
e. Click OK to close the New Listener dialog.
7. Click OK to close the New Service dialog.

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Chapter 9: Configuing and Managing an HTTPS Reverse Proxy Service
Section A: Configuring the HTTPS Reverse Proxy

8. Click Apply.

Relevant CLI Syntax to Create/Edit an HTTPS-Reverse-Proxy Service


To enter configuration mode for the service:
SGOS#(config) proxy-services
SGOS#(config proxy-services) create https-reverse-proxy service-name
SGOS#(config proxy-services) edit service-name



The following subcommands are available:
SGOS#(config service-name) add {transparent | explicit | all |
ip_address | ip_address/subnet-mask} {port | first_port-last_port}
[intercept | bypass]
SGOS#(config service-name) attribute {ccl list_name | cipher-suite
cipher-suite | forward-client-cert {enable | disable}| keyring
keyring_id | ssl-versions {sslv2 | sslv3 | tlsv1 | sslv2v3 | sslv2tlsv1
| sslv3tlsv1 | sslv2v3tlsv1} | use-adn {enable | disable}| verifyclient {enable | disable}}
SGOS#(config service-name) bypass {transparent | explicit | all |
ip_address | ip_address/subnet-mask} {port | first_port-last_port}
SGOS#(config service-name) exit
SGOS#(config service-name) intercept {transparent | explicit | all |
ip_address | ip_address/subnet-mask} {port | first_port-last_port}
SGOS#(config service-name) remove {transparent | explicit | all |
ip_address | ip_address/subnet-mask} {port | first_port-last_port}
SGOS#(config service-name) view

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Table 9–2 HTTP Origination Commands (Continued)
http

[=port_number]

server

Specifies the port number on the OCS in which
HTTP is listening.
server specifies to use the relative path for
URLs in the HTTP header because the next hop
is a Web server, not a proxy server. Proxy is the
default.

Creating Policy for HTTP and HTTPS Origination
Forwarding hosts must be already created on the ProxySG before forwarding
policy can be created.
To create a policy using CPL:

url.host=host_name forward(host_alias)

To create a policy using VPM:

1. In the VPM module, create a Forwarding layer.
2. Set the Destination to be the URL of the OCS.
Set the Action to forward to the forwarding host and configure parameters to
control forwarding behavior.

158

Chapter 10: Managing Shell Proxies

This chapter discusses how to configure the Telnet shell proxy. Shell proxies
provide shells which allow a client to connect to the ProxySG. In this version,
only a Telnet shell proxy is supported.

Topics in this Chapter
This chapter includes information about the following topics:


"About Shell Proxies" on page 159



"Customizing Policy Settings for Shell Proxies" on page 160



"About Telnet Shell Proxies" on page 161



"Configuring the Telnet Shell Proxy Service Options" on page 162



"Creating or a New Telnet Shell Proxy Service" on page 163



"Viewing Shell History Statistics" on page 166

About Shell Proxies
Using a shell proxy, you can:


terminate a Telnet protocol connection either transparently or explicitly.



authenticate users either transparently or explicitly.



view the access log.



enforce policies specified by CPL.



communicate though an upstream SOCKS gateway and HTTP proxy using
the CONNECT method.

Within the shell, you can configure the prompt and various banners using CPL
$substitutions. You can also use hard-coded text instead of CPL substitutions
(available substitutions are listed in the table below). The syntax for a CPL
substitution is:
$(CPL_property)
Table 10–1 CPL Substitutions for Shell Proxies

Substitution

Description

proxy.name or
appliance.name

Configured name of the ProxySG.

proxy.address

IP address of the appliance on which this
connection is accepted.

proxy.card

Adapter number of the appliance on which this
connection is accepted.

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Table 10–1 CPL Substitutions for Shell Proxies

Substitution

Description

client.protocol

This is telnet.

client.address

IP address of the client.

proxy.primary_address or
appliance.primary_address

Primary address of the proxy, not where the user
is connected.

release.id

SGOS version.

Customizing Policy Settings for Shell Proxies
To manage a shell proxy through policy, you can use the conditions, properties,
and actions listed below. For information on using CPL to manage shell proxies,
refer to Volume 10: Content Policy Language Guide.

Conditions
• All time and date related triggers

• proxy.address=

• All exception related triggers

• proxy.card=

• All server_url triggers

• proxy.port=

• All url triggers

• client.protocol=

• All authentication related triggers

• user-defined conditions

• category=

• client.protocol=telnet

• client.address=

• url.scheme=telnet

Properties
• allow, deny, force_deny

• force_exception(exception_id[,
details])

• action.action_name{yes|no}

• forward(alias_list | no)

• All trace() properties

• forward.fail_open(yes | no)

• All access_log() properties

• reflect_ip(auto | no | client | vip |
ip_address)

• All log.xxx() properties

• socks_gateway(alias_list | no)

• access_server(yes|no)

• socks_gateway.fail_open(yes | no)

• authenticate.force(yes|no)

• telnet.prompt(no | string)

• authenticate(realm)

• telnet.realm_banner(no | string)

• exception(exception_id[,

• telnet.welcome_banner(no | string)

details])

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The banner strings support $-sign substitutions.

Actions
:

• rewrite(url.host, host_regex_pattern,
replacement_pattern)

• log_message()

• rewrite(url, url_regex_pattern,
replacement_pattern)

• notify_email(subject, body)

• set(url_port, port_number)

• notify_snmp(message)

Boundary Conditions for Shell Proxies


A hardcoded timeout of five minutes is enforced from the acceptance of a new
connection until destination information is provided using the Telnet
command.



If proxy authentication is enabled, users have three chances to provide correct
credentials.



Users are not authenticated until destination information is provided.



Users can only enter up to an accumulated 2048 characters while providing
the destination information. (Previous attempts count against the total
number of characters.)



Connection to an upstream HTTP proxy is not encouraged.



If connections from untrustworthy IP address or subnet are not desired, then a
client IP/subnet-based deny policy must be written.

About Telnet Shell Proxies
The Telnet shell proxy allows you to manage a Telnet protocol connection to the
ProxySG. Using the Telnet shell proxy, the ProxySG performs:


Explicit termination without proxy authentication, where you explicitly
connect through Telnet to the ProxySG hostname or IP address. In this case,
the ProxySG provides a shell.



Explicit termination with proxy authentication, where after obtaining the
destination host and port information from user, the ProxySG challenges for
proxy credentials. After the correct proxy credentials are provided and
authenticated, the appliance makes an upstream connection and goes into
tunnel mode. In this case, the appliance provides a shell.



Transparent termination without proxy authentication, where the ProxySG
intercepts Telnet traffic through an L4 switch, software bridge, or any other
transparent redirection mechanism. From the destination address of TCP
socket, the ProxySG obtains OCS contact information and makes the
appropriate upstream connection, either directly or through any configured
proxy. For more information on configuring a transparent proxy, see
Appendix A: "Explicit and Transparent Proxy" on page 213.

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Transparent termination with proxy authentication, where, after intercepting
the transparent connection, the ProxySG challenges for proxy credentials.
After the correct proxy credentials are provided and authenticated, the
ProxySG makes an upstream connection and goes into tunnel mode.

After in the shell, the following commands are available:


help:

Displays available commands and their effects.



telnet server[:port]: Makes an outgoing Telnet connection to specified
server. The colon (:) between server and port can be replaced with a space,

if

preferred.


exit:

Terminates the shell session.

Configuring the Telnet Shell Proxy Service Options
This section describes how to change the default service options and add new
services.

Changing the Telnet Shell Proxy Service to Intercept All IP Addresses
on Port 23
The service is configured to listen to all IP addresses, but is set in Bypass mode.
The following procedure describes how to change the service to Intercept mode.
Default settings are:


Proxy Edition–a Telnet proxy service is configured but disabled on port 23 on
a new system.



Proxy Edition– a Telnet proxy service is not created on an upgrade.



MACH5 Edition–a transparent TCP tunnel connection listening on port 23 is
created in place of the default Telnet proxy service.

To configure the Telnet Shell proxy to intercept traffic:

1. From the Management Console, select Configuration > Services > Proxy Services.

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Related CPL Syntax to Customize Telnet Shell Proxy Settings
You can use CPL substitutions when creating welcome and realm banners and
Telnet prompts. For a list of available CPL substitutions, see Table 10–1, "CPL
Substitutions for Shell Proxies" on page 159.

Related CLI Syntax to Configure a Telnet Shell Proxy
SGOS#(config) shell {max-connections number_of_connections | prompt
prompt | realm-banner realm_banner | welcome-banner welcome_banner}

Notes for Telnet Shell Proxies


Telnet credential exchange is in plaintext.



A Telnet proxy cannot be used to communicate with non-Telnet servers (such
as Webservers on port 80) because Telnet proxies negotiate Telnet options
with the client before a server connection can be established.

Viewing Shell History Statistics
The Shell History tab displays client connections over the last 60-minute, 24-hour,
and 30-day period.
Note: The Shell history statistics are available only through the Management
Console.
To view Shell history statistics:

1. Select Statistics > Protocol Details > Shell History.

2. Select a time- period for the graph from the Duration: drop-down list. The
default setting is last hour.
3. (Optional) To set the graph scale to a different value, select a value from the
Graph scale should drop-down list.

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Chapter 11: Managing a SOCKS Proxy

This chapter discusses the ProxySG SOCKS proxy. While SOCKS servers are
generally used to provide firewall protection to an enterprise, they also can be
used to provide a generic way to proxy any TCP/IP or UDP protocols. The
ProxySG supports both SOCKSv4/4a and SOCKSv5; however, because of
increased username and password authentication capabilities and compression
support, Blue Coat recommends that you use SOCKS v5.
Note: For Blue Coat compatibility with SOCKS clients, check with customer
support. For information on the Permeo Premium Agent (Permeo PA), see
"Using the Permeo PA SOCKS Client with the Blue Coat SOCKS Server" on
page 172.

Topics in this Chapter
This chapter includes information about the following topics:


"Creating or Editing a SOCKS Proxy Service" on page 168



"Configuring the SOCKS Proxy" on page 170



"Using Policy to Control the SOCKS Proxy" on page 171



"Using the Permeo PA SOCKS Client with the Blue Coat SOCKS Server" on
page 172



"Viewing SOCKS History Statistics" on page 174

In a typical deployment, the SOCKS proxy works with the Endpoint Mapper
proxy and MAPI handoff. In this deployment, you will:


Create an Endpoint Mapper proxy at the remote office (the downstream
proxy) that intercepts Microsoft RPC traffic and creates dynamic TCP
tunnels. Traffic to port 135 is transparently redirected to this service using
bridging or L4 switch or WCCP. For information on creating and enabling
an Endpoint Mapper proxy service, see Chapter 6: "Accelerating the
Microsoft Outlook Application (Endpoint Mapper and MAPI Proxies)" on
page 83.



Create any other TCP tunnel proxies you need at the remote office: SMTP,
DNS, and the like. For information on configuring TCP tunnels, see
Chapter 13: "Managing the TCP Tunneling Proxy" on page 207.



Create a SOCKS gateway at the remote office and enable compression for
that gateway. This SOCKS gateway points to a SOCKS proxy located at the
main office location (the upstream proxy, the core of the network). For
information on creating a SOCKS gateway and enabling SOCKS
compression, see the SOCKS Gateway Configuration chapter in Volume 5:
Advanced Networking.

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e. Click OK to close the New Listener dialog.
6. Click OK to close the New Service dialog.
7. Click Apply.

Relevant CLI Syntax to Create/Edit a Proxy Service:


To enter configuration mode for the service:
SGOS#(config) proxy-services
SGOS#(config proxy-services) create socks service-name
SGOS#(config proxy-services) edit service-name



The following subcommands are available:
SGOS#(config service-name) add {explicit | ip_address | ip_address/
subnet-mask} {port | first_port-last_port} [intercept | bypass]
SGOS#(config service-name) attribute {adn-optimize {enable | disable}|
detect-protocol {enable | disable}}
SGOS#(config service-name) bypass {explicit | ip_address | ip_address/
subnet-mask} {port | first_port-last_port}
SGOS#(config service-name) intercept {explicit | ip_address |
ip_address/subnet-mask} {port | first_port-last_port}
SGOS#(config service-name) remove {explicit | ip_address | ip_address/
subnet-mask} {port | first_port-last_port}
SGOS#(config service-name) view

Configuring the SOCKS Proxy
Complete the following steps to create a SOCKS proxy and to configure SOCKSproxy connection and timeout values.
To create a SOCKS proxy server:

1. Select Configuration > Services > SOCKS Proxy.

2. Fill in the option fields (described below) as needed. The defaults are
displayed and should be sufficient for most purposes.

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Table 11–1 SOCKS Proxy Options

Option

Suboption

Description

Max-Connections

connections

Set maximum allowed SOCKS client
connections. The default of 0 indicates an
infinite number of connections are allowed.

Connection
timeout

seconds

Set maximum time to wait on an outbound
CONNECT.

Bind timeout on
accept

seconds

Set maximum time to wait on an inbound
BIND.

Minimum idle
timeout

seconds

Specifies the minimum timeout after which
SOCKS can consider the connection for
termination when the max connections are
reached.

Maximum idle
timeout

seconds

Specifies the max idle timeout value after which
SOCKS should terminate the connection.

Related CLI Syntax to Configure the SOCKS Proxy
SGOS#(config)
SGOS#(config)
SGOS#(config)
SGOS#(config)
SGOS#(config)

socks-proxy
socks-proxy
socks-proxy
socks-proxy
socks-proxy

accept-timeout seconds
connect-timeout seconds
max-connections num_connections
max-idle-timeout seconds
min-idle-timeout seconds

Using Policy to Control the SOCKS Proxy
Once the basic configuration for the SOCKS proxy has been set, you can use
policy to control the SOCKS proxy.


To use SOCKS version 5, which allows you to use a SOCKS username/
password, you must set the version through policy.


If using VPM, go to the Forwarding layer, select Source > Set Source Object >
New > SOCKS Version.



If using CPL, enter the following:
client.protocol=socks
ALLOW socks.version=5
DENY



If browsers and FTP clients are configured to use SOCKS encapsulation and a
rule in policy is matched that denies a transaction, you will see a page cannot be
displayed message instead of an exception page.
This is expected behavior, as a deny action abruptly closes the client's TCP
connection, yet the client is expecting a SOCKS-style closure of the connection.
You can avoid this, and return an exception page by applying the following
policy:

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If using VPM, go to the Web Access layer, create two rules. For the first
rule, select Service > New > Client Protocol > SOCKS > TCP Tunneling over SOCKS;
for the second, select Service > New > Client Protocol > SOCKS > All SOCKS.



If using CPL, enter the following:

DENY socks=yes tunneled=yes
DENY socks=yes

Using the Permeo PA SOCKS Client with the Blue Coat SOCKS Server
The ProxySG can be used as a SOCKS gateway by the Permeo Premium Agent
(PA), with full licensing support and Dynamic Port Management (DPM)
functionality.
The ProxySG supports the Windows Permeo PA SOCKS client version 5.12a,
including those clients that require the special probe license protocol and
corresponding customer ID. Note that each ProxySG can only support PA clients
with the same customer ID.
Licensing the PA SOCKS client on the ProxySG is a two-step process:


Get the customer ID from the PA client.



Tell the ProxySG the PA customer ID.
Note: The default license setting for the Permeo PA client on the ProxySG is
off. This setting should only be enabled when you are using the PA client.

To obtain the PA Customer ID:

1. From the PA client, launch the Permeo Agent User Properties (Start Menu > All
Programs > Permeo Premium Agent).

2. Click the About tab.

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3. Make a note of the Customer ID number, which is in hex. In the example
above the Customer ID is 1111.
To validate the Permeo PA license on the ProxySG:
Note: You cannot validate the license through the Management Console.

1. From the ProxySG, launch the CLI:
SGOS> enable
Enable Password:
SGOS# configure terminal
Enter configuration commands, one per line. End with CTRL-Z.

2. From the (config) prompt:
SGOS#(config) socks-proxy pa-customer-id customer_id

where customer_id is the Customer ID number you took from the About tab on
the PA client.
To disable the Permeo PA license:

From the (config) prompt:
SGOS#(config) socks-proxy pa-customer-id 0

Limitations


Protocol Detection interferes with SOCKS and must be disabled on the
ProxySG. The CPL policy should include the line detect_protocol(no).



SOCKS compression should be disabled when using the PA SOCKS client.
The CPL policy should include the line socks.accelerate(no).



The ProxySG only supports username and password authentication between
the ProxySG and the SOCKS Permeo PA client.

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The ping and trace route functions from Permeo PA administrator tool are not
compatible with this release (5.1).



Proxy chaining is not supported between the ProxySG and the Permeo
Application Gateway (ASG).



The policy update feature on the PA is not supported when using the
ProxySG. PA can get policy from the HTTP source as well as the ASG so it can
still perform automatic updates from a external Web server.



Only the UPWD authentication method is supported.

Viewing SOCKS History Statistics
The SOCKS History tabs (SOCKS Clients, SOCKS Connections, and SOCKS client
and server compression) display client data, Connect, Bind, and UPD Associate
requests, client and server UDP, TCP and compression requests.
Note: The SOCKS history statistics are available only through the Management

Console.

Viewing SOCKS Clients
The SOCKS Clients tab displays SOCKS Client data.
To view SOCKS client data:

1. Select Statistics > SOCKS History > SOCKS Clients.
2. Select a time period for the graph from the Duration: drop-down list.
3. (Optional) To set the graph scale to a different value, select a value from the
Graph scale should drop-down list.

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Viewing SOCKS Connections
The SOCKS Connections tab displays SOCKS Connection data.
To view SOCKS connection data:

Select Statistics > SOCKS History > SOCKS Connections.

Viewing SOCKS Client and Server Compression Gain Statistics
You can view SOCKS client and server compression-gain statistics for the
ProxySG over the last 60 minutes, 24 hours, and 30 days in the Client Comp. Gain
and the Server Comp. Gain tabs. These statistics are not available through the CLI.
The green display on the bar graph represents uncompressed data; the blue
display represents compressed data. Hover your cursor over the graph to see the
compressed gain data.
To view SOCKS client compressed gain statistics:

1. Select Statistics > SOCKS History > Client Comp. Gain.
2. Select a time priod for the graph from the Duration: drop-down list.

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3. (Optional) To set the graph scale to a different value, select a value from the
Graph scale should drop-down list.
To view SOCKS Server compressed gain statistics:

1. Select Statistics > SOCKS History > Server Comp. Gain.
2. Select a time period from the Duration: drop-down list.

3. (Optional) To set the graph scale to a different value, select a value from the
Graph scale should drop-down list.

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Chapter 12: Managing the SSL Proxy

This chapter discusses the ProxySG SSL proxy. HTTPS traffic poses a major
security risk to enterprises. Because the SSL content is encrypted, it cannot be
monitored by normal means, allowing users to bring in viruses, access
forbidden sites, or leak confidential business information over the HTTPS
connection on port 443.
The SSL proxy allows you to intercept HTTPS traffic (in explicit and
transparent modes) so that security measures such as authentication, virus
scanning and URL filtering, and performance enhancements such as HTTP
caching can be applied to HTTPS content. Additionally, the SSL proxy allows
you to validate server certificates presented by various HTTPS sites at the
gateway and offers information about the HTTPS traffic in the access log.

Topics in this Chapter
This chapter includes information about the following topics:


Section A: "Intercepting HTTPS Traffic" on page 181



Section B: "Configuring SSL Rules through Policy" on page 190



Section C: "Viewing SSL Statistics" on page 197



Section D: "Advanced Topics" on page 200

For information on Certificate Authority (CA) certificates, keyrings, and
keypairs, refer to Volume 4: Securing the Blue Coat ProxySG Appliance.

Understanding the SSL Proxy
The SSL proxy can be used to tunnel or intercept HTTPS traffic. The SSL proxy
tunnels all HTTPS traffic by default unless there is an exception, such as a
certificate error or a policy denial. In such cases the SSL proxy intercepts the
SSL connection and sends an error page to the user. The SSL proxy allows
interception of HTTPS traffic for monitoring reasons as well.
Note: Some HTTPS traffic, such as financial information, should not be
intercepted.

The SSL proxy can do the following operations while tunneling HTTPS traffic.


Validate server certificates, including revocation checks using Certificate
Revocation Lists (CRLs).



Check various SSL parameters such as cipher and version.



Log useful information about the HTTPS connection.

When the SSL proxy is used to intercept HTTPS traffic, it can also:

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Cache HTTPS content.



Apply HTTP-based authentication mechanism.



Do virus scanning and URL filtering.



Apply granular policy (such as validating mime type and filename extension).

Validating the Server Certificate
The SSL proxy can do the following checks on server certificates:


Verification of issuer signature.



Verification of certificate dates.



Comparison of hostname in the URL and certificate (intercepted connections
only).
Hostnames in server certificates are important because the SSL proxy can
identify a Web site just by looking at the server certificate if the hostname is in
the certificate. Most content-filtering HTTPS sites follow the guideline of
putting the name of the site as the common name in the server's certificate.



Verification of revocation status.
To mimic the overrides supported by browsers, the SSL proxy can be
configured to ignore failures for the verification of issuer signatures and
certificate dates and comparison of the hostname in the URL and the
certificate.

The ProxySG trusts all root CA certificates that are trusted by Internet Explorer
and Firefox. This list is updated to be in sync with the latest versions of IE and
Firefox.

Checking CRLs
An additional check on the server certificate is done through Certificate
Revocations Lists (CRLs). CRLs show which certificates are no longer valid; the
CRLs are created and maintained by Certificate Signing Authorities that issued
the original certificates.
Only CRLs that are issued by a trusted issuer can be used by the ProxySG. The
CRL issuer certificate must exist as CA certificate on the ProxySG before the CRL
can be imported.
The ProxySG allows:


One local CRL per certificate issuing authority.



An import of a CRL that is expired; a warning is displayed in the log.



An import of a CRL that is effective in the future; a warning is displayed in the
log.

Determining What HTTPS Traffic to Intercept
The SSL proxy tunnels HTTPS traffic by default; it does not intercept HTTPS
traffic.

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Many existing policy conditions, such as destination IP address and port number
can be used to decide which HTTPS connections to intercept.
Additionally, the SSL proxy allows the hostname in the server certificate to be
used to make the decision to intercept or tunnel the traffic. The server certificate
hostname can be used as is to make intercept decisions for individual sites, or it
can be categorized using any of the various URL databases supported by Blue
Coat.
Categorization of server certificate hostnames can help place the intercept
decision for various sites into a single policy rule.
Recommendations for intercepting traffic include:


Intercept Intranet traffic.



Intercept suspicious Internet sites, particularly those that are categorized as
none in the server certificate.

Managing Decrypted Traffic
After the HTTPS connection is intercepted, you can do:


Anti-virus scanning over ICAP.



URL filtering (on box and off-box). Blue Coat recommends on box URL/
content filtering if you use transparent proxy. When the URL is sent off-box
for filtering, only the hostname or IP address of the URL (not the full path) is
sent for security reasons.



Filtering based on the server certificate hostname.



Caching.

HTTPS applications that require browsers to present client certificates to secure
Web servers do not work if you are intercepting traffic. Create a policy rule to
prevent the interception of such applications.
If you intercept HTTPS traffic, be aware that local privacy laws might require you
to notify the user about interception or obtain consent prior to interception. You
can use the HTML Notify User object to notify users after interception. You can
use consent certificates to obtain consent prior to interception. The HTML Notify
User is easier; however, the ProxySG must decrypt the first request from the user
before it can issue an HTML notification page.

Using the SSL Proxy with ADN Optimization
The SSL proxy itself can be used as a split proxy, which requires two SSL proxies,
one at the branch and one at the core, working together. A split proxy can be
configured (see below) to implement functionality that is not possible in a
standalone proxy.
In this configuration, the SSL proxy supports ADN optimization on WAN
networks, and SSL traffic performance can be increased through the byte caching
capability offered. The branch proxy, which makes the decisions, is configured
with both ADN optimization and SSL proxy functionality.

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The concentrator proxy (a ProxySG that provides access to data center resources)
does not require any configuration related to the SSL proxy. It only requires the
necessary ADN configuration for applying byte caching capabilities to
intercepted SSL content.
No special configuration is required to the SSL proxy. Securing the tunnels and
authenticating the devices occurs from the Configuration > ADN panes.

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System Configuration:

System Configuration:

ADN Optimization
Device Authentication and Authorization
SSL Proxy Configuration
ADN Secure Tunnel

ADN Optimization
Device Authentication and Authorization
ADN Secure Tunnel

Chapter 12: Managing the SSL Proxy
Section A: Intercepting HTTPS Traffic

Section A: Intercepting HTTPS Traffic
Intercepting HTTPS traffic (by decrypting SSL connections at the ProxySG) allows
you to apply security measures like virus scanning and URL filtering.
Configuration to intercept HTTPS traffic requires the following tasks:


Determine whether you are using transparent or explicit mode. For
information on explicit versus transparent proxies, see Appendix A: "Explicit
and Transparent Proxy" on page 213.



Create an SSL service or HTTP/SOCKS services with protocol detection
enabled, depending on whether you are using transparent or explicit mode.
For more information on creating an SSL service, skip to "Setting Up the SSL
Proxy in Transparent Proxy Mode" on page 182.



Create or import an issuer keyring, which is used to sign emulated server
certificates to clients on the fly, allowing the SSL proxy to examine SSL
content. For more information on creating an issuer keyring, see "Specifying
an Issuer Keyring and CCL Lists for SSL Interception" on page 185.



(Optional) Use the Notify User object or client consent certificates to notify users
that their requests are being intercepted and monitored. Whether this is
required depends on local privacy laws. Note that the ProxySG has to decrypt
the first request from the user to issue an HTML notification page. If this is not
desirable, use client consent certificates instead. For more information on
configuring the Notify User object, refer to Volume 7: Managing Content. For
information on managing client consent certificates, see "Using Client Consent
Certificates" on page 186.



Download CA certificates to desktops to avoid a security warning from the
client browsers when the ProxySG is intercepting HTTPS traffic. For
information, see "Downloading an Issuer Certificate" on page 186.



Using policy (VPM or CPL), create rules to intercept SSL traffic and to control
validation of server certificates. By default, such traffic is tunneled and not
intercepted. You must create suitable policy before intercepting SSL traffic. For
more information on using policy to intercept SSL traffic, see Section B:
"Configuring SSL Rules through Policy" on page 190.



Configure the Blue Coat AV or other third-party ICAP vendor, if you have not
already done this. For more information on ICAP-based virus scanning, refer
to Volume 7: Managing Content.



Configure the Blue Coat Web Filter (BCWF) or a third-party URL-filtering
vendor, if you have not already done this. For more information on
configuring BCWF, refer to Volume 7: Managing Content.



Configure Access Logging. For more information on configuring access
logging, refer to Volume 8: Access Logging.



Customize Exception Pages: To customize exception pages (in case of server
certificate verification failure), refer to Volume 6: The Visual Policy Manager and
Advanced Policy.

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Setting Up the SSL Proxy in Transparent Proxy Mode
Proxy services are configured from the Management Console or the CLI. If using
the SSL proxy in transparent mode, continue with this section.
If you are using the SSL proxy in explicit mode, you might need an HTTP proxy
or a SOCKS proxy. For information on configuring an SSL proxy in explicit mode,
see "Setting Up the SSL Proxy in Explicit Proxy Mode" on page 184.
You can use a TCP Tunnel service in transparent mode to get the same
functionality. A TCP tunnel service is useful when you have a combination of SSL
and non-SSL traffic going over port 443 and you do not want to break the non-SSL
traffic. The SSL service requires that all requests to its port be SSL.
To configure an SSL service in transparent proxy mode:

1. From the Management Console, select Configuration > Services > Proxy Services.
2. Click New.

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The Optimize Bandwidth option is selected by default if you enabled WAN
optimization during initial configuration. Clear the option if you are not
configuring WAN optimization.

8. Create a new listener:
a. Click New; if you edit an existing listener, click Edit.
b. Define the IP address option: explicit or the specified address.
c. In the Port Range field, enter the ports on which the service should
listen. The default port for SSL is 443.
d. Select the default behavior for the service: Bypass tells the service to
ignore any traffic. Intercept configures the service to intercept the traffic
that is being proxied.
e. Click OK to close the dialog.
9. Click OK to close the Edit Service dialog.
10. Click Apply.
Continue with "Specifying an Issuer Keyring and CCL Lists for SSL Interception"
on page 185.

Related CLI Syntax to Create/Edit an SSL Proxy Service:


To enter configuration mode for the service:
SGOS#(config) proxy-services
SGOS#(config proxy-services) create service-type service-name
SGOS#(config proxy-services) edit service-name



The following subcommands are available:
SGOS#(config service-name) add {transparent | ip_address | ip_address/
subnet-mask} {port | first_port-last_port} [intercept | bypass]
SGOS#(config service-name) attribute {adn-optimize {enable | disable}
| use-adn {enable | disable}}
SGOS#(config service-name) bypass {transparent | ip_address |
ip_address/subnet-mask} {port | first_port-last_port}
SGOS#(config service-name) exit
SGOS#(config service-name) intercept {transparent | ip_address |
ip_address/subnet-mask} {port | first_port-last_port}
SGOS#(config service-name) remove {transparent | ip_address |
ip_address/subnet-mask} {port | first_port-last_port}
SGOS#(config service-name) view

Setting Up the SSL Proxy in Explicit Proxy Mode
The SSL proxy can be used in explicit mode in conjunction with the HTTP Proxy
or SOCKS Proxy. You must create an HTTP Proxy service or a SOCKS Proxy
service and use it as the explicit proxy from desktop browsers. You must also
ensure that the detect-protocol attribute is enabled for these services.

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Section A: Intercepting HTTPS Traffic

When requests for HTTPS content are sent to either a SOCKS proxy or an HTTP
proxy, the proxies can detect the use of the SSL protocol on such connections and
enable SSL proxy functionality.
For information on configuring a new explicit HTTP or SOCKS proxy service, see
"Creating an Explicit Proxy Server" on page 214.
Continue with "Specifying an Issuer Keyring and CCL Lists for SSL Interception"
on page 185.

Specifying an Issuer Keyring and CCL Lists for SSL Interception
The SSL proxy can emulate server certificates; that is, present a certificate that
appears to come from the origin content server. In actuality, Blue Coat has
emulated the certificate and signed it using the issuer keyring. By default only the
subjectName and the expiration date from the server certificate are copied to the
new certificate sent to the client.
Note: Only keyrings with both a certificate and a keypair can be used as issuer
keyrings.

You can also change the CA Certificate Lists (CCLs) that contain the CAs to be
trusted during client and server certificate validation. The defaults are adequate
for the majority of situations. For more information about CCLs, refer to Volume 4:
Securing the Blue Coat ProxySG Appliance.
To specify the keyring and CCLs:

1. From the Management Console, select Configuration > Proxy Settings > SSL Proxy.

2. Issuer Keyring: From the drop-down menu, select the keyring to use as the
issuer keyring. Any keyring with both a certificate and a keypair in the dropdown menu can be used.
3. CCL for Client Certificates: Choose which CAs are trusted when the SSL proxy
validates client certificates. The default is .
4. CCL for Server Certificates: Choose which CAs are trusted when the SSL proxy
validates server certificates.The CCL for server certificates is relevant even
when SSL proxy is tunneling SSL traffic. The default is browser-trusted.
5. Click Apply.
To configure policy, see "Configuring SSL Rules through Policy" on page 190.

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Related CLI Syntax to Specify the Keyring and CCL Lists
This procedure assumes a keyring has already been created.
SGOS#(config ssl) proxy issuer-keyring keyring_name
SGOS#(config ssl) proxy client-cert-ccl {ccl_list_name | all | none}
SGOS#(config ssl) proxy server-cert-ccl {ccl_list_name | all}

Using Client Consent Certificates
The SSL proxy, in forward proxy deployments, can specify whether a client
(typically a browser) certificate is required. These certificates are used for user
consent, not for user authentication. Whether they are needed depends upon local
privacy laws.
With client consent certificates, each user is issued a pair of certificates with the
corresponding private keys. Both certificates have a meaningful user-readable
string in the common name field. One certificate has a string that indicates grant of
consent something like: “Yes, I agree to SSL interception”. The other certificate has
a common name indicating denial of consent, something like: “No, I do not agree
to SSL interception”.
Policy is installed on the ProxySG to look for these common names and to allow
or deny actions. For example, when the string “Yes, I agree to SSL interception” is
seen in the client certificate common name, the connection is allowed; otherwise,
it is denied.
To configure client consent certificates:

1. Install the issuer of the client consent certificates as a CA certificate.
2. In VPM, configure the Require Client Certificate object in the SSL Layer > Action
column.
3. Configure the Client Certificate object in the Source column to match common
names.

Downloading an Issuer Certificate
When the SSL proxy intercepts an SSL connection, it presents an emulated server
certificate to the client browser. The client browser issues a security pop-up to the
end-user because the browser does not trust the issuer used by the ProxySG. This
pop-up does not occur if the issuer certificate used by SSL proxy is imported as a
trusted root in the client browser's certificate store.
The ProxySG makes all configured certificates available for download via its
management console. You can ask end users to download the issuer certificate
through Internet Explorer or Firefox and install it as a trusted CA in their browser
of choice. This eliminates the certificate popup for emulated certificates.
To download the certificate through Internet Explorer, see "To download a
certificate through Internet Explorer:" on page 187. To download a certificate
through Firefox, see "To download a certificate through Firefox:" on page 188.

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To download a certificate through Internet Explorer:
Note: You can e-mail the console URL corresponding to the issuer certificate to

end users so that the he or she can install the issuer certificate as a trusted CA.
1. Select Statistics > Advanced.
2. Select SSL.
3. Click Download a Certificate as a CA Certificate; the list of certificates on the system
display.
4. Click a certificate (it need not be associated with a keyring); the File Download
Security Warning displays asking what you want to do with the file.

5. Click Save. When the Save As dialog box displays, click Save; the file
downloads.
6. Click Open to view the Certificate properties; the Certificate window displays.

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7. Click the Install Certificate button to launch the Certificate Import Wizard.
8. Ensure the Automatically select the certificate store based on the type of certificate
radio button is enabled before completing the wizard
9. Click Finish. the wizard announces when the certificate is imported.
10. (Optional) To view the installed certificate, go to Internet Explorer, Select Tools
> Internet Options > Contents > Certificates, and open either the Intermediate
Certification Authorities tab or the Trusted Root Certification Authorities tab,
depending on the certificate you downloaded.
To download a certificate through Firefox:
Note: You can e-mail the console URL corresponding to the issuer certificate
to end users so that the end-user can install the issuer certificate as a trusted
CA.

1. Select Statistics > Advanced.
2. Select SSL.
3. Click Download a ProxySG Certificate as a CA Certificate; the list of certificates on
the system display.
4. Click a certificate (it need not be associated with a keyring); the Download
Certificate dialog displays.

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5. Enable the options needed. View the certificate before trusting it for any
purpose.
6. Click OK; close the Advanced Statistics dialog.

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Section B: Configuring SSL Rules through Policy
SSL interception and access rules, including server certificate validation, are
configured through policy—either the VPM or CPL. Use the SSL Intercept Layer to
configure SSL interception; use the SSL Access Layer to control other aspects of SSL
communication such as server certificate validation and SSL versions. To
configure SSL rules using CPL, skip to "CPL in the SSL Intercept Layer" on page
194.
This section covers the following topics:


"Using the SSL Intercept Layer" on page 190.



"Using the SSL Access Layer" on page 192



"Using Client Consent Certificates" on page 186

Using the SSL Intercept Layer
The SSL intercept layer allows you to set intercept options:


"To intercept HTTPS content through VPM:" on page 190



"To intercept HTTPS requests to specific sites through VPM:" on page 191



"To customize server certificate validation through VPM:" on page 193

For a list of policy conditions, properties, and actions, see "CPL in the SSL
Intercept Layer" on page 194.
Note: For detailed instructions on using VPM, refer to Volume 6: The Visual Policy

Manager and Advanced Policy.
To intercept HTTPS content through VPM:

1. Select Configuration > Policy > Visual Policy Manager and launch VPM.
2. From the Policy drop-down menu, select Add SSL Intercept Layer.
3. Right-click Set in the Action column; the Set Action object displays.
4. Click New and select Enable HTTPS Intercept object or the Enable HTTPS Intercept
on Exception object.

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To categorize hostnames in server certificates through VPM:

1. While still in the Destination column of the SSL Intercept layer, right-click Set;
the Set Destination object displays.
2. Click New and select the Server Certificate Category object. The Add Server
Certificate Category Object displays. You can change the name in the top field if
needed.

3. Select the categories. The categories you selected display in the right-hand
column.
4. Click OK.

Using the SSL Access Layer
For a list of the conditions, properties, and actions that can be used in the SSL
Access layer, see "CPL in the SSL Layer" on page 195.
Note: For detailed instructions on using VPM, refer to Volume 6: The Visual
Policy Manager and Advanced Policy.

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To customize server certificate validation through VPM:
Note: The policy property server.certificate.validate, if set, overrides the
ssl-verify-server

command for either HTTP or for forwarding hosts.

1. Select Configuration > Policy > Visual Policy Manager and launch VPM.
2. From the Policy drop-down menu, select Add SSL Access Layer.
3. In the Action column, right-click Set; the Set Action object displays.
4. Click New and select Set Server Certificate Validation object.

5. By default, server certificate validation is enabled; to disable it, select Disable
server certificate validation at the bottom of the dialog.
If server certificate validation is enabled, you can determine behavior by
selecting checkboxes to Ignore a hostname mismatch, Ignore certificate expiration, or
Ignore untrusted issuer. These overrides mimic the overrides supported by most
browsers.
You can add server certificates to the ProxySG to allow proper validation. For
more information, refer to Volume 4: Securing the Blue Coat ProxySG Appliance.
6. If you want to check the CA certificate revocation list (CRL) from a Certificate
Authority, verify Also check certification revocation is selected. For information
on using CRL, see "Checking CRLs" on page 178.

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CPL in the SSL Intercept Layer
Note: VPM is much easier to use than CPL. All CPL gestures except the
ssl.forward_proxy.server_keyring

property, used only for troubleshooting, are

also in VPM.
The following CPL gestures can be used in the SSL Intercept layer:
Note: No authentication-related triggers are allowed in the SSL Intercept layer.

Allowed Properties (allowed in the SSL Intercept layer only):
• ssl.forward_proxy( )

• ssl.forward_proxy.splash_text( )

• ssl.forward_proxy.hostname( )

• trace.destination( )

• ssl.forward_proxy.issuer_keyring • trace.request( )
( )

• ssl.forward_proxy.server_keyring • trace.rules( )
( )

• ssl.forward_proxy.splash_url( )

• ssl.forward_proxy.server_keyring
(used for troubleshooting only)

Allowed Actions
• log_message( )

• notify_snmp( )

• notify_email( )



Allowed Conditions
• category

• proxy.port

• client.address

• server.certificate.hostname

• client.host

• server.certificate.hostname.category

• client.host.has_name

• server.certificate.subject

• client.protocol

• server_url.*

• proxy.address

• url.*

• proxy.card



An example of using CPL to intercept SSL traffic is:

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;create list of servers to intercept
define condition server_intercept_list
server.certificate.hostname.category=webmail
server.certificate.hostname=porn.com
server.certificate.hostname.category=gambling
server.certificate.hostname.category=none
end condition server_intercept_list

; value no means tunnel, value https means intercept as forward proxy
condition=server_intercept_list ssl.forward_proxy(https)
ssl.forward_proxy(no)

Note: For detailed instructions on using CPL, including detailed explanations of

the gestures listed here, refer to Volume 10: Content Policy Language Guide

CPL in the SSL Layer
The following CPL gestures can be used in the SSL layer (called SSL Access layer
in VPM):

Allowed Actions (allowed in the SSL layer only)
• server.certificate. • server.certificate.
validate(yes | no)

validate.
check_revocation
(local | no))

• client.certificate. • client.certificate.
validate(yes | no)

validate.
check_revocation
(local | no)

• server.certificate.
validate.ignore
(hostname_mismatch |
expiration | untrusted
_issuer)

• client.certificate.
require(yes)

Allowed Conditions and Properties
• client.connection.
negotiated_ssl_version
= (condition)

• client.certificate. • client.certificate.
common_name.regex
=

subject.dn = DN>

• client.certificate.comm • client.certificate. • client.certificate.
on_
name[.exact|.substring
|
.prefix|.suffix] =


• server.certificate.
hostname[.exact|
.substring|.prefix|.su
ffix]=

subject
[.exact|.substring
|
.prefix|.suffix|.r
egex] =

subject.regex =


• server.certificate. • server.certificate.
hostname.regex=


hostname. category =


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• server.certificate
.hostname.category =!
st> (condition)

• ssl.proxy_mode=

• server.connection.
negotiated_cipher
=

• server.connection.
negotiated_cipher.
strength =
low | medium | high
| export

• client.protocol=
tunneled=

Note: For detailed instructions on using CPL, including detailed explanations of

the gestures listed here, refer to Volume 10: Content Policy Language Guide.

Notes
Note: Pipelining configuration for HTTP is ignored for HTTPS requests

intercepted by the SSL proxy. When the SSL proxy intercepts an HTTPS request,
and the response is an HTML page with embedded images, the embedded
images are not pre-fetched by the ProxySG.

196



If the ProxySG and the origin content server cannot agree on a common cipher
suite for intercepted connections, the connection is aborted.



Server-Gated Cryptography and step-up certificates are treated just as regular
certificates; special extensions present in these certificates are not be copied
into the emulated certificate. Clients relying on SGC/step-up certificates
continue using weaker ciphers between the client and the ProxySG when the
SSL proxy intercepts the traffic.

Chapter 12: Managing the SSL Proxy
Section C: Viewing SSL Statistics

Section C: Viewing SSL Statistics
SSL History Statistics
The Statistics > Protocol details > SSL History tabs (Unintercepted SSL Data, Unintercepted
SSL Clients, Unintercepted SSL Bytes) provide various useful statistics for
unintercepted SSL traffic.
Note: Some SSL statistics (SSL client connections and total bytes sent and

received over a period of time) can only be viewed through the Management
Console (see "Unintercepted SSL Data" on page 197 and "Unintercepted SSL
Clients" on page 198).

Unintercepted SSL Data
The Unintercepted SSL Data tab on the Management Console displays SSL statistics.
The following table details the statistics provided through the Unintercepted SSL
Data tab.
Table 12–1 Unintercepted SSL Data Statistics

Status

Description

Current Unintercepted SSL Sessions

The current number of unintercepted SSL client
connections.

Total Unintercepted SSL Sessions

The cumulative number of unintercepted SSL
client connections since the ProxySG was last
rebooted.

Total Bytes Sent

The total number of unintercepted bytes sent.

Total Bytes Received

The total number of unintercepted bytes received.

To view unintercepted SSL data statistics:

From the Management Console, select Statistics > Protocol Details > SSL History >
Unintercepted SSL Data.
The default view shows all unintercepted SSL data.

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Unintercepted SSL Clients
The Unintercepted SSL Clients tab displays dynamic graphical statistics for
connections received in the last 60-minute, 24-hour, or 30-day period.
To view SSL client unintercepted statistics:

1. From the Management Console, select Statistics > Protocol Details > SSL History >
Unintercepted SSL Clients.

2. Select a time period for the graph from the Duration: drop-down list. The
default is Last Week.
3. (Optional) To set the graph scale to a different value, select a value from the
Graph scale should drop-down list.

Unintercepted SSL Bytes
The Unintercepted SSL Bytes tab displays dynamic graphical statistics for bytes
received in the last 60-minute, 24-hour, or 30-day period.
To view unintercepted SSL byte statistics:

1. From the Management Console, select Statistics > Protocol Details > SSL History >
Unintercepted SSL Bytes.

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2. Select the Duration: for the graph from the drop-down list. The default is Last
week.
3. (Optional) To set the graph scale to a different value, select a value from the
Graph scale should drop-down list.

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Section D: Advanced Topics
If you use OpenSSL or Active Directory, you can follow the procedures below to
manage your certificates.
For OpenSSL, see "Creating an Intermediate CA using OpenSSL" on page 200; if
using Active Directory, see "Creating an Intermediate CA using Microsoft Server
2003 (Active Directory)" on page 203.

Creating an Intermediate CA using OpenSSL
This section describes the certificate management when creating an intermediate
CA using OpenSSL.
The overall steps are:


"Installing OpenSSL" on page 200



"Creating a Root Certificate" on page 200



"Modifying the OpenSSL.cnf File" on page 201



"Signing the ProxySG CSR" on page 202



"Importing the Certificate into the ProxySG" on page 202



"Testing the Configuration" on page 202

Various OpenSSL distributions can be found at http://www.openssl.org.

Installing OpenSSL
After OpenSSL is installed, you must edit the openssl.cnf file and ensure the
pathnames are correct. By default root certificates are located under ./PEM/DemoCA;
generated certificates are located under /certs.

Creating a Root Certificate
In order to create a root Certificate Authority (CA) certificate, complete the
following steps.
Note: The key and certificate in this example is located at ./bin/PEM/demoCA/
private/.

1. Open a MS-DOS window, and enter:
openssl req -new -x509 -keyout
c:\resources\ssl\openssl\bin\PEM\demoCA\private\
cakey.pem -out
c:\resources\ssl\openssl\bin\PEM\demoCA\private\CAcert.pem

where the root directory for openssl is: \resources\ssl\openssl

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openssl req -new -x509 -keyout
c:\resources\ssl\openssl\bin\PEM\demoCA\private\cakey.pem -out
c:\resources\ssl\openssl\bin\PEM\demoCA\private\CAcert.pem
Using configuration from C:\Resources\SSL\OpenSSL\bin\openssl.cnf
Loading 'screen' into random state - done
Generating a 1024 bit RSA private key
.....................................+++++
................................................+++++
writing new private key to
'c:\resources\ssl\openssl\bin\PEM\demoCA\private\cakey.pem'
Enter PEM pass phrase:

2. Type any string more than four characters for the PEM pass phrase.
3. Enter the certificate parameters, such as country name, common name that are
required for a Certificate Signing Request (CSR).
The private key and root CA are now located under the directory ./PEM/
DemoCA/private

4. Create a ProxySG keyring.
a. From the Management Console, select Configuration > SSL > Keyrings.
b. Click Create; fill in the fields as appropriate.
c. Click OK.
5. Create a CSR on the ProxySG.
a. From the Management Console, select Configuration > SSL > Keyrings.
b. Highlight the keyring you just created; click Edit/View.
c. In the Certificate Signing Request pane, click Create and fill in the fields
as appropriate.
Note: Detailed instructions on creating a keyring and a CSR are in Volume 4:

Securing the Blue Coat ProxySG Appliance. They can also be found in the
online help.
6. Paste the contents of the CSR into a text file called new.pem located in the ./bin
directory.

Modifying the OpenSSL.cnf File
Modify the openssl.cnf file to import the openSSL root CA into your browser. If
you do not do this step, you must import he ProxySG certificate into the browser.
1. In the openssl.cnf file, look for the string basicConstraints=CA, and set it to
TRUE.
basicConstraints=CA:TRUE

2. Save the openSSL.cnf file.

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Signing the ProxySG CSR
Open a MS-DOS window and enter:
openssl ca -policy policy_anything -out newcert.pem -in new.pem

The output is:
Using configuration from C:\Resources\SSL\OpenSSL\bin\openssl.cnf
Enter PEM pass phrase:
Check that the request matches the signature
Signature ok
The Subjects Distinguished Name is as follows
countryName
:PRINTABLE:'FR'
stateOrProvinceName
:PRINTABLE:'Paris'
localityName
:PRINTABLE:'Paris'
organizationName
:PRINTABLE:'BlueCoat'
organizationalUnitName:PRINTABLE:'Security Team'
commonName
:PRINTABLE:'ProxySG.bluecoat.com'
emailAddress
:IA5STRING:'[email protected]'
Certificate is to be certified until Sep 27 13:29:09 2006 GMT (365
days)
Sign the certificate? [y/n]:y
1 out of 1 certificate requests certified, commit? [y/n]y
Write out database with 1 new entries
Data Base Updated

This signs the certificate; it can then be imported into the ProxySG.

Importing the Certificate into the ProxySG
1. Open the file newcert.pem in a text editor.
2. Select Management Console > Configuration > SSL > SSL Keyrings.
3. Selecting the keyring used for SSL interception; click Edit/View.
4. Paste in the contents of the newcert.pem file.
5. Import the contents of the newcert.pem file into the CA Certificates list.
a. From the Management Console, select Configuration > SSL > CA
Certificates.
b. Click Import; enter the certificate name in the CA Cert Name field.
c. Paste the certificate, being sure to include the -----BEGIN
CERTIFICATE---- and the ----END CERTIFICATE----- statements in
the ./bin/PEM/demoCA/private/CAcert file.
d. Click OK.
Note: Detailed instructions on importing a CA certificate are in

Chapter 9: "Configuing and Managing an HTTPS Reverse Proxy Service"
on page 151.

Testing the Configuration
Import the root CA into your browser and construct an SSL interception policy.

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Note: Detailed instructions on constructing an SSL interception policy are in
Section B: "Configuring SSL Rules through Policy" on page 190.

You should not be prompted for any certificate warning.

Creating an Intermediate CA using Microsoft Server 2003 (Active Directory)
This section describes certificate management when creating an intermediate CA
using Active Directory.
Before you begin:


Verify the Windows 2003 system is an Active Directory server.



Make sure IIS is installed.



Install the "Certificate Services" through the control panel



Select the mode to be Enterprise root CA.

All certificate management is done through the browser using the following URL:
http://@ip_server/CertSrv

For information on the following tasks, see:


"To install the root CA onto the browser:" on page 203



"To create a ProxySG keyring and certificate signing request:" on page 203



"To sign the ProxySG CSR:" on page 204



"To import the certificate onto the ProxySG:" on page 204



"To test the configuration:" on page 204

To install the root CA onto the browser:

1. Connect to http://@ip_server/CertSrv.
2. Click Download a CA Certificate.
3. Click Install this CA Certificate chain.
This installs the root CA onto the browser.
To create a ProxySG keyring and certificate signing request:

1. From the Management Console, select SSL > Keyrings.
2. Create a new keyring. For detailed instructions on creating a new keyring,
refer to Volume 4: Securing the Blue Coat ProxySG Appliance.
3. Create a Certificate Signing Request (CSR). For detailed instructions on
creating a CSR, refer to Volume 4: Securing the Blue Coat ProxySG Appliance.
4. Click OK.

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To sign the ProxySG CSR:

1. Connect to http://@ip_server/CertSrv.
2. Select the option Request a certificate.
3. Select Submit an advanced certificate request and then Submit a certificate request by
using a base 64 encoded …

4. Paste the contents of the CSR.
5. Select the Certificate Template Subordinate Certification Authority.
If this template does not exist, connect to the certificate manager tool on the
Active Directory server and add the template.
6. Click on Submit.
7. Download the certificate (not the chain) as Base 64 encoded.
8. Save this file on the workstation as newcert.pem.
To import the certificate onto the ProxySG:

1. Open the file newcert.pem in a text editor.
2. In the Management Console, select Configuration > SSL > SSL Keyrings.
3. Select the keyring that has the CSR created; click Edit/View.
Note: Make sure this keyring is used as the issuer keyring for emulated

certificates. Use policy or the SSL intercept setting in the Management
Console or the CLI.
4. Paste the contents of the newcert.pem file.
5. Import the contents of the newcert.pem file into the CA Certificates list.
a. From the Management Console, select Configuration > SSL > CA
Certificates.
b. Click Import; enter the certificate name in the CA Cert Name field.
c. Paste the certificate, being sure to include the -----BEGIN
CERTIFICATE---- and the ----END CERTIFICATE----- statements in
the ./bin/PEM/demoCA/private/CAcert file.
d. Click OK.
Note: Detailed instructions on importing a CA certificate are in
Chapter 9: "Configuing and Managing an HTTPS Reverse Proxy Service"
on page 151.
To test the configuration:

Import the root CA into your browser and construct a SSL interception policy.
Note: Detailed instructions on constructing an SSL interception policy are in
Section B: "Configuring SSL Rules through Policy" on page 190.

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You should not be prompted for any certificate warning.

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Chapter 13: Managing the TCP Tunneling Proxy

This chapter discusses managing traffic through the ProxySG TCP Tunneling
Proxy. Tunneling, or port forwarding, is a way to forward TCP traffic. Any
application protocol running over TCP can be tunneled using this service.
Client-server applications carry out any authentication procedures just as they
do when TCP tunneling is not involved.
SGOS uses a tcp:// scheme for TCP-tunnel transactions instead of HTTPS
because SGOS does not actually know that it is HTTPS that is being tunneled.
You can use ADN optimization in conjunction with TCP tunnels to compress
and accelerate the tunneled traffic. Both explicit and transparent TCP tunneling
are supported. Which one you use depends on your needs.


Explicit TCP tunneling allows connections to one of the ProxySG's IP
addresses.



Transparent TCP tunneling allows connections to any IP address other than
those belonging to the ProxySG. TCP tunneling in transparent mode
supports categorization as well as blocking of destination IP address, port,
host, and domain.

Note: The TCP-Tunnel service does not support content filtering with

Websense offbox or ICAP.

Topics in this Chapter
This chapter includes information about the following topics:


"TCP-Tunnel Proxy Services Supported" on page 207



"Creating or Editing a TCP-Tunnel Proxy Service" on page 208

TCP-Tunnel Proxy Services Supported
A number of proxy services are supported with the TCP-Tunnel proxy. For the
most current list, see Table 3–5: "Proxy Name and Listeners" on page 55.
In addition, the default proxy service (which listens on all ports not assigned to
other services), uses the TCP-Tunnel proxy. The default proxy service has only
one listener; its action can be set to bypass or intercept. No new listeners can be
added to the default proxy service, and the default listener and service cannot
be deleted. Service attributes can be changed.
To keep the ProxySG from interfering with unassigned traffic, set the behavior
to bypass.
An access log entry is available for every TCP tunnel connection.

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Enabling ADN does not guarantee the connections are accelerated by
ADN. The actual enable decision is determined by ADN routing (for
explicit deployment) and network setup (for transparent deployment).
b. The Optimize Bandwidth option is selected by default if you enabled
ADN optimization during initial configuration. Clear the option if you
are not configuring ADN optimization.
7. Create a new listener:
a. Click New.
b. Define the IP address option: explicit or the specified address.
c. In the Port Range field, enter the ports on which the service should
listen. The default ports for each service are listed in Table 3–5, "Proxy
Name and Listeners" on page 55.
d. Select the default action for the service: Bypass tells the service to
ignore any traffic. Intercept configures the service to intercept the traffic
that is being proxied.
If you selected Optimize all other TCP traffic during initial configuration, all
listeners in services that use the TCP-Tunnel proxy intercept traffic. If you
did not select Optimize all other TCP traffic, TCP-Tunnel listeners bypass all
traffic by default.
e. Click OK to close the listener dialog.
8. Click OK to close the service dialog.
9. Click Apply.

Related CLI Syntax to Create/Edit a Tunneling Proxy Service


To enter configuration mode:
SGOS#(config) proxy-services
SGOS#(config proxy-services) create tcp-tunnel service-name
SGOS#(config proxy-services) edit service-name



The following subcommands are available:
SGOS#(config service-name) add {transparent | explicit | all |
ip_address | ip_address/subnet-mask} {port | first_port-last_port}
[intercept | bypass]
SGOS#(config service-name) attribute {adn-optimize {enable | disable}|
detect-protocol {enable | disable}| early-intercept {enable |
disable}| use-adn {enable | disable}}
SGOS#(config service-name) bypass {transparent | explicit | all |
ip_address | ip_address/subnet-mask} {port | first_port-last_port}
SGOS#(config service-name) exit
SGOS#(config service-name) intercept {transparent | explicit | all |
ip_address | ip_address/subnet-mask} {port | first_port-last_port}
SGOS#(config service-name) remove {transparent | explicit | all |
ip_address | ip_address/subnet-mask} {port | first_port-last_port}
SGOS#(config service-name) view

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If you created a transparent TCP-Tunnel service, the procedure is complete. If you
created an explicit TCP-Tunnel service, you must configure a forwarding
destination port.
To configure a forwarding destination port:

1. Create a forwarding destination port, where the ProxySG directs traffic.
SGOS#(config proxy-services tcp-tunnel) exit
SGOS#(config proxy-services) exit
SGOS#(config) forwarding
SGOS#(config forwarding) create host_alias ip_address tcp=port

2. (Optional) View the results:
SGOS#(config forwarding) view
Forwarding Groups: (* = host unresolved)
No forwarding groups defined.
Individual Hosts: (* = host unresolved)
Host_Alias 10.25.36.47 tcp=port_number

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Appendix A: Explicit and Transparent Proxy

Whether you select explicit or transparent proxy deployment is determined by
factors such as network configuration, number of desktops, desired user
experience, and desired authentication approach.
Note: While you must configure proxying to do authentication, verify the

proxy is configured correctly and is functioning before adding authentication
to the mix. Many network or other configuration problems can appear similar
to authentication errors.

About the Explicit Proxy
In an explicit proxy configuration, the client (browser) is explicitly configured
to use a proxy server. The browser is given the IP address and port number of
the proxy service (the ProxySG). It is also possible to configure the browser to
download the proxy settings from a Web server. This is called a Proxy AutoConfiguration (PAC) file. When a user makes a request, the browser connects
to the proxy service and sends the request. Because the browser knows it is
talking to a proxy, the browser provides the proxy server with the destination
server.
The proxy service accepts the explicit connection to it, and fetches the request
from the browser. The request identifies the desired origin content server
(OCS) and the resource on that server. The proxy service uses this information
to contact the OCS if necessary.
The disadvantage to explicit proxy is that each desktop must be properly
configured to use the proxy, which might not be feasible in a large
organization.
Note: Explicit proxy allows a redundant configuration using IP address
failover among a cluster of machines. For information on creating a redundant
configuration for failover, refer to Volume 5: Advanced Networking.

About the Transparent Proxy
When transparent proxy is enabled, the client (browser) does not know the
traffic is being processed by a machine other than the OCS. The browser
believes it is talking to the OCS, so the request is formatted for the OCS and the
proxy determines for itself the destination server based on information in the
request, such as the destination IP address in the packet, or the Host: header in
the request.
To enable the ProxySG to intercept traffic sent to it, you must create a service
and define it as transparent. The service is configured to intercept traffic for a
specified port, or for all IP addresses on that port. A transparent HTTP proxy,
for example, typically intercepts all traffic on port 80 (all IP addresses).

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To make sure that the appropriate traffic is directed to the ProxySG, deploy
hardware such as a Layer-4 switch or a WCCP router, or the ProxySG’s software
bridge that can redirect selected traffic to the appliance. Traffic redirection is
managed through polices you create on the redirection device.
For detailed information on explicit proxies, continue with the next section; for
detailed information on transparent proxies, continue with "Transparent Proxies"
on page 215.
For information on creating an explicit proxy server, regardless of proxy type,
continue with "Creating an Explicit Proxy Server" on page 214.

Creating an Explicit Proxy Server
If your network does not use transparent proxy, clients on the network must
configure their browsers to use either an explicit proxy server or a Proxy AutoConfiguration (PAC) file.
Two PAC files ship with the ProxySG:


default PAC file



accelerated PAC file

They can be accessed at:


https://ProxySG_IP_Address:8082/accelerated_pac_base.pac



https://ProxySG_IP_Address:8082/proxy_pac_file

Note: Only the accelerated_pac_base.pac file can be edited. Any text editor

can be used.
The ProxySG generates client instructions that describe how to configure
Microsoft Internet Explorer, Netscape Communicator, and Firefox based on
instructions selected by the ProxySG administrator. You can configure client
instructions for each network adapter in the ProxySG with the Configuration >
Network > Adapters > Interface > Settings button.
After selecting client instructions, the ProxySG administrator directs clients to go
to the ProxySG home page and follow the instructions in the Browser
Configuration section. The ProxySG detects the browser installed on the client
and displays the appropriate instructions.

Using the ProxySG as an Explicit Proxy
To use the ProxySG as an explicit proxy and use services such as SOCKS or FTP,
you must provide custom instructions to clients instructing them how to
configure their browsers to use the ProxySG as a proxy server.
This is a two-step process, requiring that you add the proxy IP address to the
browser and also instruct the ProxySG which adapter interface uses the proxy IP
address.
Before the proxy can be used, you must:


214

Configure the proxy server.

Appendix A: Explicit and Transparent Proxy



Enable the explicit proxy (whether a service or a server).

The browsers described here are Internet Explorer 6.0 and Firefox 1.5. If you have
different browsers or different versions of Internet Explorer or Firefox, refer to the
vendor documentation for information on configuring proxies.
From Internet Explorer:

1. Select Tools > Internet Options > Connections > LAN Settings.
2. Click Use a proxy server.
3. Enter the IP address and port number for the proxy, or click Advanced to set
proxy server IP addresses and port numbers for services such as HTTP, FTP,
and SOCKS. (Configure HTTPS through the Secure field.)
4. Click OK to exit the Advanced Settings tab, then continue to click OK until you
exit the Tools menu.
From Firefox:

1. Select Tools > Options > Genera l> Connection Settings.
2. Click Manual proxy configuration.
3. Enter proxy server IP addresses and port numbers for services such as HTTP,
FTP, SOCKS, and SSL.
4. Click OK; click OK again.

Configuring Adapter Proxy Settings
Once the explicit proxy is configured on the browser, decide which adapter
interfaces listen for which service. Each adapter interface can listen for only one IP
address; you can configure multiple proxies on one ProxySG using the same IP
address.
To provide configuration instructions on the ProxySG:

1. Select Configuration > Network > Adapters.
2. In the Adapter pane, select the adapter you want to use. If an adapter does not
exist, the Adapter pane displays the word Empty.
3. In the Interface pane, select the correct interface. Click Settings.
4. Select Using a proxy.
5. Click OK to close the Settings dialog.

Relevant CLI Syntax to Configure Adapter Proxy Settings
SGOS#(config) interface fast-ethernet interface_#

Transparent Proxies
A transparent proxy can be configured several ways:


Through hardware: See "Configuring Transparent Proxy Hardware" on page
216.

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Through bridging: "Bridging" on page 216.



Through using the ProxySG as a gateway: See "Configuring IP Forwarding"
on page 217.

In addition to the transparent proxy configuration, you must create a proxy
service for the transparent proxy and enable the service. At this time, you can also
set other attributes for the service, including the destination IP address and port
range. For information on creating or editing a proxy service for transparent
configuration, see Chapter 3: "About Proxy Services and Proxies" on page 27.

Configuring Transparent Proxy Hardware
For transparent proxy to work, you must use one of the following:


A bridge, either hardware or software



Layer-4 switch



WCCP

Bridging
Network bridging through the ProxySG provides transparent proxy pass-through
and failover support. This functionality allows ProxySGs to be deployed in
environments where L4 switches and WCCP-capable routers are not feasible
options.
The ProxySG provides bridging functionality by two methods:


Software—A software, or dynamic, bridge is constructed using a set of
installed interfaces. Within each logical bridge, interfaces can be assigned or
removed. Note that the adapters must of the same type. Although the
software does not restrict you from configuring bridges with adapters of
different types (10/100 or GIGE), the resultant behavior is unpredictable.
To set up a software bridge, refer to Volume 1: Getting Started.



Hardware—The Blue Coat Pass-Through card is a 10/100 dual interface
Ethernet device that enables a bridge, using its two adapters, so that packets
can be forwarded across it. However, if the system crashes, the Pass-Through
card becomes a network: the two Ethernet cables are connected so that traffic
can continue to pass through without restriction.
When the Pass-Through card is installed on the ProxySG, a bridge is
automatically created and traffic going through the bridge is intercepted
according to the proxy-service setting. Note that:

216



Forwarding traffic behavior: By default, the bridge forwards packets that
are not to be intercepted.



Proxy request behavior: Requests are proxied on either adapter, so if you
connect one side of the bridge to your Internet connection, there might be
a number of issues.

Appendix A: Explicit and Transparent Proxy

Configuring a Layer-4 Switch
In transparent proxy acceleration, as traffic is sent to the origin content server, any
traffic sent on port 80 is redirected to the ProxySG by the Layer 4 switch. The
benefits to using a Layer 4 switch include:


Built-in failover protection. In a multi-ProxySG setup, if one fails, the Layer 4
switch can route to the next ProxySG.



Request partitioning based on IP address instead of on HTTP transparent
proxying. (This feature is not available on all Layer 4 switches.)



ProxySG bypass prevention. You can configure a Layer 4 device to always go
through the ProxySG even for requests to a specific IP address.



ProxySG bypass enabling. You can configure a Layer 4 device to never go
through the ProxySG.

For information on configuring a layer-4 switch, refer to the manufacturer’s
documentation.

Configuring a WCCP-Capable Router
WCCP is a Cisco®-developed protocol that allows you to establish redirection of
the traffic that flows through routers.
The main benefits of using WCCP are:


Scalability—With no reconfiguration overhead, redirected traffic can be
automatically distributed to up to 32 ProxySGs.



Redirection safeguards—If no ProxySGs are available, redirection stops and
the router forwards traffic to the original destination address.

For information on using WCCP with a ProxySG, refer to Volume 5: Advanced
Networking.

Configuring IP Forwarding
IP Forwarding is a special type of transparent proxy. The ProxySG is configured
to act as a gateway and is configured so that if a packet is addressed to the
ProxySG adapter, but not its IP address, the packet is forwarded toward the final
destination. If IP forwarding is disabled, the packet is rejected as being misaddressed.
By default, IP forwarding is disabled to maintain a secure network.
Important:

When IP forwarding is enabled, be aware that all ProxySG ports are
open and all the traffic coming through them is not subjected to policy, with the
exception of the ports that have explicitly defined through the Configuration >
Services > Proxy Services tab.

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To enable IP forwarding:

1. Select Configuration > Network > Routing > Gateways.
2. Select the Enable IP forwarding checkbox at the bottom of the pane.
3. Click OK; click Apply.

Related CLI Syntax to Enable IP Forwarding
SGOS#(config) tcp-ip ip-forwarding enable

See Also


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Volume 5: Advanced Networking, Chapter 2

Glossary

A
access control list—Allows

or denies specific IP addresses access to a server.

access log—A list of all the requests sent to a ProxySG. You can read an access
log using any of the popular log-reporting programs. When a client uses HTTP
streaming, the streaming entry goes to the same access log.
account—A

named entity that has purchased the ProxySG or the Entitlements
from Blue Coat.
activation code—A

string of approximately 10 characters that is generated and
mailed to customers when they purchase the ProxySG.

active content stripping—Provides a way to identify potentially dangerous mobile

or active content and scripts, and strip them out of a response.
active content types—Used in the Visual Policy Manager. Referring to Web
Access policies, you can create and name lists of active content types to be
stripped from Web pages. You have the additional option of specifying a
customized message to be displayed to the user
administration access policy—A

policy layer that determines who can access the
ProxySG to perform administrative tasks.

administration authentication policy—A

policy layer that determines how
administrators accessing the ProxySG must authenticate.
AJAX—Acronym

for Asynchronous JavaScript and XML, the technology used
for live updating of Web objects without having to reload the entire page.

Application Delivery Network (ADN)—A

WAN that has been optimized for
acceleration and compression by Blue Coat. This network can also be secured
through the use of appliance certificates. An ADN network is composed of an
ADN manager and backup ADN manager, ADN nodes, and a network
configuration that matches the environment.
ADN backup manager—Takes over for the ADN manager in the event it becomes
unavailable. See ADN manager.
ADN manager—Responsible for publishing the routing table to SG Clients (and
to other ProxySG appliances).
ADN optimize attribute—Controls whether to optimize bandwidth usage when
connecting upstream using an ADN tunnel.
A record—The central records of DNS, which

link a domain or subdomain to an
IP address. An A record can correspond to a single IP address or many IP
addresses.

asx rewrite—Allows you to rewrite URLs and then direct a client's subsequent
request to the new URL. One of the main applications of ASX file rewrites is to
provide explicit proxy-like support for Windows Media Player 6.4, which
cannot set explicit proxy mode for protocols other than HTTP.

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audit—A

log that provides a record of who accessed what and how.

authenticate-401 attribute—All transparent and explicit requests received on the port
always use transparent authentication (cookie or IP, depending on the
configuration). This is especially useful to force transparent proxy authentication
in some proxy-chaining scenarios
authenticated content—Cached content that requires authentication at the origin
content server (OCS). Supported authentication types for cached data include
basic authentication and IWA (or NTLM).
authentication—Allows you to verify the identity of a user. In its simplest form, this

is done through usernames and passwords. Much more stringent authentication
can be employed using digital certificates that have been issued and verified by a
Certificate Authority. See also basic authentication, proxy authentication, and SSL
authentication.
authentication realm—Authenticates

and authorizes users to access SG services
using either explicit proxy or transparent proxy mode. These realms integrate
third-party vendors, such as LDAP, Windows, and Novell, with the Blue Coat
operating system.

authorization—The

permissions given to an authenticated user.

B
bandwidth—The

amount of data you can send through a network or modem
connection, usually measured in bits per second (bps).

bandwidth class—A defined

unit of bandwidth allocation.

bandwidth class hierarchy—A gouping of bandwidth classes into a tree structure
that specifies the relationship among different classes. You create a hierarchy by
creating at least one parent class and assigning other classes as its children.
bandwidth gain—Bandwidth

gain is a calculation of the savings that occur when
bandwidth is not consumed as a result of some form of optimization.
For example, bandwidth gain for active sessions is calculated by subtracting the
number of client bytes from the number of server bytes and dividing the result by
the number of server bytes.
(Client Bytes - Server Bytes) / Server Bytes

bandwidth management—Classify,

control, and, if needed, limit the amount of
bandwidth used by network traffic flowing in or out of a ProxySG.

basic authentication—The

standard authentication for communicating with the
target as identified in the URL.

BCAAA—Blue Coat Authentication and Authorization Agent. Allows SGOS 5.x to
manage authentication and authorization for IWA, CA eTrust SiteMinder realms,
Oracle COREid, Novell, and Windows realms. The agent is installed and
configured separately from SGOS 5.x and is available from the Blue Coat Web site.
BCLP—Blue

Coat Licensing Portal.

byte-range support—The

ability of the ProxySG to respond to byte-range requests
(requests with a Range: HTTP header).

220

C
cache—An

"object store," either hardware or software, that stores information
(objects) for later retrieval. The first time the object is requested, it is stored,
making subsequent requests for the same information much faster.

A cache helps reduce the response time and network bandwidth consumption on
future, equivalent requests. The ProxySG serves as a cache by storing content
from many users to minimize response time and prevent extraneous network
traffic.
cache control—Allows

you to configure which content the ProxySG stores.

cache efficiency—A tab found on the Statistics pages of the Management Console
that shows the percent of objects served from cache, the percent loaded from the
network, and the percent that were non-cacheable.
cache hit—Occurs when the ProxySG receives a request for an object and can serve

the request from the cache without a trip to the origin server.
cache miss—Occurs

when the ProxySG receives a request for an object that is not
in the cache. The ProxySG must then fetch the requested object from the origin
server.

cache object—Cache contents includes all objects currently stored by the ProxySG.
Cache objects are not cleared when the ProxySG is powered off.
Certificate Authority (CA)—A

trusted, third-party organization or company that
issues digital certificates used to create digital signatures and public key/private
key pairs. The role of the CA is to guarantee that the individuals or company
representatives who are granted a unique certificate are who they claim to be.

child class (bandwidth gain)—The child of a parent class is dependent on that parent
class for available bandwidth (they share the bandwidth in proportion to their
minimum/maximum bandwidth values and priority levels). A child class with
siblings (classes with the same parent class) shares bandwidth with those siblings
in the same manner.
cipher suite—Specifies the algorithms used to secure an SSL connection. When a
client makes an SSL connection to a server, it sends a list of the cipher suites that it
supports.
client consent certificates—A certificate that indicates acceptance or denial of
consent to decrypt an end user's HTTPS request.
client-side transparency—A

way of replacing the ProxySG IP address with the Web
server IP address for all port 80 traffic destined to go to the client. This effectively
conceals the ProxySG address from the client and conceals the identity of the
client from the Web server.

concentrator—A

ProxySG, usually located in a data center, that provides access to
data center resources, such as file servers.
content filtering—A way of controlling which content is delivered to certain users.
ProxySG appliances can filter content based on content categories (such as
gambling, games, and so on), type (such as http, ftp, streaming, and mime type),
identity (user, group, network), or network conditions. You can filter content
using vendor-based filtering or by allowing or denying access to URLs.

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D
default boot system—The system that was successfully started last time. If a system
fails to boot, the next most recent system that booted successfully becomes the
default boot system.
default proxy listener—See

proxy service (default).

denial of service (DoS)—A

method that hackers use to prevent or deny legitimate
users access to a computer, such as a Web server. DoS attacks typically send many
request packets to a targeted Internet server, flooding the server's resources and
making the system unusable. Any system connected to the Internet and equipped
with TCP-based network services is vulnerable to a DoS attack.
The ProxySG resists DoS attacks launched by many common DoS tools. With a
hardened TCP/IP stack, the ProxySG resists common network attacks, including
traffic flooding.

destination objects—Used

in Visual Policy Manager. These are the objects that
define the target location of an entry type.

detect protocol attribute—Detects the protocol being used. Protocols that can be
detected include: HTTP, P2P (eDonkey, BitTorrent, FastTrack, Gnutella), SSL, and
Endpoint Mapper.
diagnostic reporting—Found in the Statistics pane, the Diagnostics tab allows you to

control whether Daily Heartbeats and/or Blue Coat Monitoring are enabled or
disabled.
directives—Commands used in installable lists to configure forwarding and
SOCKS gateway.
DNS access—A

policy layer that determines how the ProxySG processes DNS

requests.
domain name system (DNS)—An

Internet service that translates domain names into

IP addresses.
dynamic bypass—Provides a maintenance-free method for improving performance
of the ProxySG by automatically compiling a list of requested URLs that return
various kinds of errors.
dynamic real-time rating (DRTR)—Used

in conjunction with the Blue Coat Web Filter
(BCWF), DRTR (also known as dynamic categorization) provides real-time analysis
and content categorization of requested Web pages to solve the problem of new
and previously unknown uncategorized URLs—those not in the database.
When a user requests a URL that has not already been categorized by the BCWF
database (for example, a brand new Web site), the ProxySG dynamic
categorization service analyzes elements of the requested content and assigns a
category or categories. The dynamic service is consulted only when the installed
BCWF database does not contain category information for an object.

E
early intercept attribute—Controls

whether the proxy responds to client TCP
connection requests before connecting to the upstream server. When early
intercept is disabled, the proxy delays responding to the client until after it has
attempted to contact the server.

222

ELFF-compatible format—A

log type defined by the W3C that is general enough to
be used with any protocol.
emulated certificates—Certificates

that are presented to the user by the ProxySG
when intercepting HTTPS requests. Blue Coat emulates the certificate from the
server and signs it, copying the subjectName and expiration. The original
certificate is used between the ProxySG and the server.

encrypted log—A

log is encrypted using an external certificate associated with a
private key. Encrypted logs can only be decrypted by someone with access to the
private key. The private key is not accessible to the ProxySG.

EULA—End

user license agreement.

event logging—Allows you to specify the types of system events logged, the size of

the event log, and to configure Syslog monitoring. The ProxySG can also notify
you by email if an event is logged. See also access logging.
explicit proxy—A configuration in which the browser is explicitly configured to
communicate with the proxy server for access to content. This is the default for
the ProxySG and requires configuration for both the browser and the interface
card.
extended log file format (ELFF)—A variant of the common log file format, which has
two additional fields at the end of the line—the referer and the user agent fields.

F
fail open/closed—Failing

open or closed applies to forwarding hosts and groups
and SOCKS gateways. Fail open or closed applies when health checks are
showing sick for each forwarding or SOCKS gateway target in the applicable failover sequence. If no systems are healthy, the ProxySG fails open or closed,
depending on the configuration. If closed, the connection attempt simply fails.
If open, an attempt is made to connect without using any forwarding target (or
SOCKS gateway). Fail open is usually a security risk; fail closed is the default if no
setting is specified.

filtering—See

content filtering.

forward proxy—A

proxy server deployed close to the clients and used to access
many servers. A forward proxy can be explicit or transparent.

FTP—See

Native FTP and Web FTP.

G
gateway—A

device that serves as entrance and exit into a communications

network.

H
hardware serial number—A string that uniquely identifies the ProxySG; it is assigned

to each unit in manufacturing.
health check tests—The method of determining network connectivity, target
responsiveness, and basic functionality. The following tests are supported:

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ICMP



TCP



SSL



HTTP



HTTPS



Group



Composite and reference to a composite result



ICAP



Websense



DRTR rating service

health check type—The kind of device or service the specific health check tests. The
following types are supported:



Forwarding host and forwarding group



SOCKS gateway and SOCKS gateway group



CAP service and ICAP service group



Websense off-box service and Websense off-box service group



DRTR rating service



User-defined host and a user-defined composite

heartbeat—Messages

sent once every 24 hours that contain the statistical and
configuration data for the ProxySG, indicating its health. Heartbeats are
commonly sent to system administrators and to Blue Coat. Heartbeats contain no
private information, only aggregate statistics useful for pre-emptively diagnosing
support issues.
The ProxySG sends emergency heartbeats whenever it is rebooted. Emergency
heartbeats contain core dump and restart flags in addition to daily heartbeat
information.

host affinity—The

attempt to direct multiple connections by a single user to the
same group member. Host affinity is closely tied to load balancing behavior; both
should be configured if load balancing is important.

host affinity timeout—The host affinity timeout determines how long a user remains

idle before the connection is closed. The timeout value checks the user's IP
address, SSL ID, or cookie in the host affinity table.

I
inbound traffic (bandwidth gain)—Network

packets flowing into the ProxySG.
Inbound traffic mainly consists of the following:


224

Server inbound: Packets originating at the origin content server (OCS) and
sent to the ProxySG to load a Web object.



Client inbound: Packets originating at the client and sent to the ProxySG
for Web requests.

installable list—A

list of configuration parameters that can be created using a text
editor (either Blue Coat or another text editor) or through the CLI inline
commands. The list can then be downloaded to the ProxySG from an HTTP server
or locally from your PC. Configurations that can be created and installed this way
include the SG Client, archiving, forwarding hosts, SOCKS gateways, ICP, policy
files, and exceptions.
integrated host timeout—An

integrated host is an origin content server (OCS) that
has been added to the health check list. The host, added through the
integrate_new_hosts property, ages out of the integrated host table after
being idle for the specified time. The default is 60 minutes.

intervals—Time

period from the completion of one health check to the start of the
next health check.

IP reflection—Determines how the client IP address is presented to the origin server

for explicitly proxied requests. All proxy services contain a reflect-ip attribute,
which enables or disables sending of client's IP address instead of the IP address
of the ProxySG.
issuer keyring—The keyring used by the ProxySG to sign emulated certificates. The

keyring is configured on the appliance and managed through policy.

L
licensable component (LC)—(Software)

A subcomponent of a license; it is an option
that enables or disables a specific feature.

LCAMS—License

Configuration and Management System.

license—Provides

both the right and the ability to use certain software functions
within a ProxyAV (or ProxySG) appliance. The license key defines and controls
the license, which is owned by an account.

listener—The service that is listening on a specific port. A listener can be identified

by any destination IP/subnet and port range. Multiple listeners can be added to
each service.
live content—Also

called live broadcast. Used in streaming, it indicates that the
content is being delivered fresh.

LKF—License

key file.

load balancing—A

way to share traffic requests among multiple upstream systems
or multiple IP addresses on a single host.

local bypass list—A

list you create and maintain on your network. You can use a
local bypass list alone or in conjunction with a central bypass list.

local policy file—Written by enterprises (as opposed to the central policy file written

by Blue Coat); used to create company- and department-specific advanced
policies written in the Blue Coat Policy Language (CPL).

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log facility—A

separate log that contains a single logical file and supports a single
log format. It also contains the file’s configuration and upload schedule
information as well as other configurable information such as how often to rotate
(switch to a new log) the logs at the destination, any passwords needed, and the
point at which the facility can be uploaded.

log format—The type of log that is used: NCSA/Common, SQUID, ELFF,
SurfControl, or Websense.

The proprietary log types each have a corresponding pre-defined log format that
has been set up to produce exactly that type of log (these logs cannot be edited). In
addition, a number of other ELFF type log formats are also pre-defined (im, main,
p2p, ssl, streaming). These can be edited, but they start out with a useful set of log
fields for logging particular protocols understood by the ProxySG. It is also
possible to create new log formats of type ELFF or Custom which can contain any
desired combination of log fields.
log tail—The access log tail shows the log entries as they get logged. With high
traffic on the ProxySG, not all access log entries are necessarily displayed.
However, you can view all access log information after uploading the log.

M
MACH5—SGOS

5 MACH5 Edition.

Management Console—A

graphical Web interface that lets you to manage,
configure, monitor, and upgrade the ProxySG from any location. The
Management Console consists of a set of Web pages and Java applets stored on
the ProxySG. The appliance acts as a Web server on the management port to serve
these pages and applets.

management information base (MIB)—Defines

the statistics that management systems
can collect. A managed device (gateway) has one or more MIBs as well as one or
more SNMP agents, which implements the information and management
functionality defined by a specific MIB.

maximum object size—The

maximum object size stored in the ProxySG. All objects
retrieved that are greater than the maximum size are delivered to the client but are
not stored in the ProxySG.

Media Access Control (MAC) address—A

unique value associated with a network
adapter; also known as hardware address or physical address. For the ProxySG, it
is a hardware address that is stored in each network card (such as an SSL
accelerator card or a Quad GigE Fiber LX card) on the ProxySG. The MAC
address uniquely identifies an adapter on a LAN and is a 12-digit hexadecimal
number (48 bits in length).
MIME/FILE type filtering—Allows

organizations to implement Internet policies for
both uploaded and downloaded content by MIME or FILE type.
multi-bit rate—The capability of a single stream to deliver multiple bit rates to
clients requesting content from ProxySG appliances from within varying levels of
network conditions (such as different connecting bandwidths and traffic).
multicast—Used

in streaming; the ability for hundreds or thousands of users to
play a single stream.

226

multicast aliases—Used

in streaming; a streaming command that specifies an alias
for a multicast URL to receive an .nsc file. The .nsc files allows the multicast
session to obtain the information in the control channel
multicast station—Used in streaming; a defined location on the proxy where the
Windows Media player can retrieve streams. A multicast station enables multicast
transmission of Windows Media content from the cache. The source of the
multicast-delivered content can be a unicast-live source, a multicast (live) source,
and simulated live (video-on-demand content converted to scheduled live
content).
multimedia content services—Used

in streaming; multimedia support includes Real
Networks, Microsoft Windows Media, Apple QuickTime, MP3, and Flash.

N
name inputing—Allows a ProxySG to resolve host names based on a partial name
specification. When a host name is submitted to the DNS server, the DNS server
resolves the name to an IP address. If the host name cannot be resolved, Blue Coat
adds the first entry in the name-inputing list to the end of the host name and
resubmits it to the DNS server
native FTP—Native

FTP involves the client connecting (either explicitly or
transparently) using the FTP protocol; the ProxySG then connects upstream
through FTP (if necessary).

NCSA common log format—Blue

Coat products are compatible with this log type,
which contains only basic HTTP access information.

network address translation (NAT)—The process of translating private network (such
as intranet) IP addresses to Internet IP addresses and vice versa. This
methodology makes it possible to match private IP addresses to Internet IP
addresses even when the number of private addresses outnumbers the pool of
available Internet addresses.
non-cacheable objects—A number of objects are not cached by the ProxySG because
they are considered non-cacheable. You can add or delete the kinds of objects that
the appliance considers non-cacheable. Some of the non-cacheable request types
are:



Pragma no-cache, requests that specify non-cached objects, such as when
you click refresh in the Web browser.



Password provided, requests that include a client password.



Data in request that include additional client data.



Not a GET request.

.nsc file—Created

from the multicast station definition and saved through the
browser as a text file encoded in a Microsoft proprietary format. Without an .nsc
file, the multicast station definition does not work.

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NTP—To

manage objects in an appliance, a ProxySG must know the current
Universal Time Coordinates (UTC) time. By default, the ProxySG attempts to
connect to a Network Time Protocol (NTP) server to acquire the UTC time. The
ProxySG includes a list of NTP servers available on the Internet, and attempts to
connect to them in the order they appear in the NTP server list on the NTP tab.

O
object (used in caching)—An

object is the item that is stored in an appliance. These
objects can be frequently accessed content, content that has been placed there by
content publishers, or Web pages, among other things.

object (used in Visual Policy Manager)—An

object (sometimes referred to as a
condition) is any collection or combination of entry types you can create
individually (user, group, IP address/subnet, and attribute). To be included in an
object, an item must already be created as an individual entry.

object pipelining—This

patented algorithm opens as many simultaneous TCP
connections as the origin server will allow and retrieves objects in parallel. The
objects are then delivered from the appliance straight to the user's desktop as fast
as the browser can request them.

Online Certificate Status Protocol (OCSP)— An Internet protocol used for obtaining the

revocation status of an X.509 digital certificate. OCSP was created as an
alternative to certificate revocation lists (CRL), specifically addressing certain
problems associated with using CRLs in a public key infrastructure (PKI). OCSP
servers are called OCSP responders due to the request/response nature of these
messages.
origin content server (OCS)—Also

called origin server. This is the original source of
the content that is being requested. An appliance needs the OCS to acquire data
the first time, to check that the content being served is still fresh, and to
authenticate users.

outbound traffic (bandwidth gain)—Network packets flowing out of the ProxySG.
Outbound traffic mainly consists of the following:



Client outbound: Packets sent to the client in response to a Web request.



Server outbound: Packets sent to an OCS or upstream proxy to request a
service.

P
PAC (Proxy AutoConfiguration) scripts—Originally created by Netscape, PACs are a
way to avoid requiring proxy hosts and port numbers to be entered for every
protocol. You need only enter the URL. A PAC can be created with the needed
information and the local browser can be directed to the PAC for information
about proxy hosts and port numbers.
packet capture (PCAP)—Allows

filtering on various attributes of the Ethernet frame
to limit the amount of data collected. You can capture packets of Ethernet frames
going into or leaving a ProxySG.

228

parent class (bandwidth gain)—A

class with at least one child. The parent class must
share its bandwidth with its child classes in proportion to the minimum/
maximum bandwidth values or priority levels.

passive mode data connections (PASV)—Data connections initiated by an FTP client to

an FTP server.
pipelining—See

object pipelining.

policies—Groups

of rules that let you manage Web access specific to the needs of
an enterprise. Policies enhance ProxySG feature areas such as authentication and
virus scanning, and let you control end-user Web access in your existing
infrastructure.

policy-based bypass list—Used in policy. Allows a bypass based on the properties of
the client, unlike static and dynamic bypass lists, which allow traffic to bypass the
appliance based on destination IP address. See also dynamic bypass.
policy layer—A

collection of rules created using Blue Coat CPL or with the VPM.

pragma: no cache (PNC)—A

metatag in the header of a request that requires the
appliance to forward a request to the origin server. This allows clients to always
obtain a fresh copy.

proxy—Caches

content, filters traffic, monitors Internet and intranet resource
usage, blocks specific Internet and intranet resources for individuals or groups,
and enhances the quality of Internet or intranet user experiences.
A proxy can also serve as an intermediary between a Web client and a Web server
and can require authentication to allow identity-based policy and logging for the
client.
The rules used to authenticate a client are based on the policies you create on the
ProxySG, which can reference an existing security infrastructure—LDAP,
RADIUS, IWA, and the like.

Proxy Edition—SGOS

5 Proxy Edition.

proxy service—The proxy service defines the ports, as well as other attributes. that
are used by the proxies associated with the service.
proxy service (default)—The default proxy service is a service that intercepts all
traffic not otherwise intercepted by other listeners. It only has one listener whose
action can be set to bypass or intercept. No new listeners can be added to the
default proxy service, and the default listener and service cannot be deleted.
Service attributes can be changed.
ProxySG—A

Blue Coat security and cache box that can help manage security and
content on a network.

public key certificate—An

electronic document that encapsulates the public key of
the certificate sender, identifies this sender, and aids the certificate receiver to
verify the identity of the certificate sender. A certificate is often considered valid if
it has been digitally signed by a well-known entity, which is called a Certificate
Authority (such as VeriSign).

public virtual IP (VIP)—Maps multiple servers to one IP address and then propagates
that information to the public DNS servers. Typically, there is a public VIP known
to the public Internet that routes the packets internally to the private VIP. This
enables you to “hide” your servers from the Internet.

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Volume 2: Proxies and Proxy Services

R
real-time streaming protocol (RTSP)—A

standard method of transferring audio and
video and other time-based media over Internet-technology based networks. The
protocol is used to stream clips to any RTP-based client.

reflect client IP attribute—Enables the sending of the client's IP address instead of the
SG's IP address to the upstream server. If you are using an application delivery
network (ADN), this setting is enforced on the concentrator proxy through the
Configuration > App. Delivery Network > Tunneling tab.
registration—An

event that binds the appliance to an account, that is, it creates the
Serial#, Account association.

remote authentication dial-in user service (RADIUS)—Authenticates

user identity via

passwords for network access.
Return to Sender (RTS)—A way of allowing outgoing TCP packets to use the same
network interface on which the corresponding incoming TCP packets arrived.
The destination Media Acess Control (MAC) address for the outgoing packets is
the same as the source MAC address of the incoming packets. See also Media
Access Control (MAC) address.
reverse proxy—A proxy that acts as a front end to a small number of predefined
servers, typically to improve performance. Many clients can use it to access the
small number of predefined servers.
routing information protocol (RIP)—Designed

to select the fastest route to a
destination. RIP support is built into ProxySG appliances.

router hops—The
RTS—See

number of jumps a packet takes when traversing the Internet.

Return to Sender.

S
secure shell (SSH)—Also

known as Secure Socket Shell. SSH is an interface and
protocol that provides strong authentication and enables you to securely access a
remote computer. Three utilities—login, ssh, and scp—comprise SSH. Security via
SSH is accomplished using a digital certificate and password encryption.
Remember that the Blue Coat ProxySG requires SSH1. A ProxySG supports a
combined maximum of 16 Telnet and SSH sessions.

serial console—A

third-party device that can be connected to one or more Blue
Coat appliances. Once connected, you can access and configure the appliance
through the serial console, even when you cannot access the appliance directly.
server certificate categories—The hostname in a server certificate can be categorized

by BCWF or another content filtering vendor to fit into categories such as
banking, finance, sports.
server portals—Doorways

that provide controlled access to a Web server or a
collection of Web servers. You can configure Blue Coat appliances to be server
portals by mapping a set of external URLs onto a set of internal URLs.

230

server-side transparency—The ability for the server to see client IP addresses, which

enables accurate client-access records to be kept. When server-side transparency
is enabled, the appliance retains client IP addresses for all port 80 traffic to and
from the ProxySG. In this scheme, the client IP address is always revealed to the
server.
service attributes—Define the parameters, such as explicit or transparent, cipher
suite, and certificate verification, that the ProxySG uses for a particular service.
sibling class (bandwidth gain)—A

bandwidth class with the same parent class as

another class.
signed system image—Cryptographically

signed with a key known only to Blue
Coat, and the signature is verified when the image is downloaded to the system.

simple network management protocol (SNMP)—The standard operations and
maintenance protocol for the Internet. It consists of a set of standards for network
management, including an application layer protocol, a database schema, and a
set of data objects. In SNMP, the available information is defined by management
information bases (MIBs), which describe the structure of the management data.
simulated live—Used

in streaming. Defines playback of one or more video-ondemand files as a scheduled live event, which begins at a specified time. The
content can be looped multiple times, or scheduled to start at multiple start times
throughout the day.

SmartReporter log type—A

proprietary ELFF log type that is compatible with the
SmartFilter SmartReporter tool.

SOCKS—A

proxy protocol for TCP/IP-based networking applications that allows
users transparent access across the firewall. If you are using a SOCKS server for
the primary or alternate forwarding gateway, you must specify the appliance’s ID
for the identification protocol used by the SOCKS gateway. The machine ID
should be configured to be the same as the appliance’s name.

SOCKS proxy—A generic way to proxy TCP and UDP protocols. The ProxySG
supports both SOCKSv4/4a and SOCKSv5; however, because of increased
username and password authentication capabilities and compression support,
Blue Coat recommends that you use SOCKS v5.
splash page—The custom message page that displays the first time you start the
client browser.
split proxy—Employs

co-operative processing at the branch and the core to
implement functionality that is not possible in a standalone proxy. Examples of
split proxies include:


Mapi Proxy



SSL Proxy

SQUID-compatible format—A

log type that was designed for cache statistics and is
compatible with Blue Coat products.
squid-native log format—The

Squid-compatible format contains one line for each

request.
SSL authentication—Ensures

that communication is with “trusted” sites only.
Requires a certificate issued by a trusted third party (Certificate Authority).

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Volume 2: Proxies and Proxy Services

SSL client—See

SSL device profile.

SSL device profile—Used to determine various SSL parameters for outgoing HTTPS
connections. Specifically, its role is to:



Identify the SSL protocol version that the ProxySG uses in negotiations
with origin servers.



Identify the cipher suites used.



Determine which certificate can be presented to origin servers by
associating a keyring with the profile.

SSL interception—Decrypting

SSL connections.

SSL proxy—A proxy that can be used for any SSL traffic (HTTPS or not), in either
forward or reverse proxy mode.
static route—A manually-configured route that specifies the transmission path a
packet must follow, based on the packet’s destination address. A static route
specifies a transmission path to another network.
statistics—Every

Blue Coat appliance keeps statistics of the appliance hardware
and the objects it stores. You can review the general summary, the volume,
resources allocated, cache efficiency, cached contents, and custom URLs generated
by the appliance for various kinds of logs. You can also check the event viewer for
every event that occurred since the appliance booted.

stream—A flow of a single type of data, measured in kilobits per second (Kbps). A
stream could be the sound track to a music video, for example.
SurfControl log type—A proprietary log type that is compatible with the SurfControl
reporter tool. The SurfControl log format includes fully-qualified usernames
when an NTLM realm provides authentication. The simple name is used for all
other realm types.
syslog—An

event-monitoring scheme that is especially popular in Unix
environments. Most clients using Syslog have multiple devices sending messages
to a single Syslog daemon. This allows viewing a single chronological event log of
all of the devices assigned to the Syslog daemon. The Syslog format is: “Date Time
Hostname Event.”
system cache—The software cache on the appliance. When you clear the cache, all
objects in the cache are set to expired. The objects are not immediately removed
from memory or disk, but a subsequent request for any object requested is
retrieved from the origin content server before it is served.

T
TCP window size—The number of bytes that can be buffered before the sending host

must wait for an acknowledgement from the receiving host.
time-to-live (TTL) value—Used

in any situation where an expiration time is needed.
For example, you do not want authentication to last beyond the current session
and also want a failed command to time out instead of hanging the box forever.
traffic flow (bandwidth gain)—Also

referred to as flow. A set of packets belonging to
the same TCP/UDP connection that terminate at, originate at, or flow through the
ProxySG. A single request from a client involves two separate connections. One of

232

them is from the client to the ProxySG, and the other is from the ProxySG to the
OCS. Within each of these connections, traffic flows in two directions—in one
direction, packets flow out of the ProxySG (outbound traffic), and in the other
direction, packets flow into the ProxySG (inbound traffic). Connections can come
from the client or the server. Thus, traffic can be classified into one of four types:


Server inbound



Server outbound



Client inbound



Client outbound

These four traffic flows represent each of the four combinations described above.
Each flow represents a single direction from a single connection.
transmission control protocol (TCP)—TCP, when used in conjunction with IP (Internet

Protocol) enables users to send data, in the form of message units called packets,
between computers over the Internet. TCP is responsible for tracking and
handling, and reassembly of the packets; IP is responsible for packet delivery.
transparent proxy—A configuration in which traffic is redirected to the ProxySG
without the knowledge of the client browser. No configuration is required on the
browser, but network configuration, such as an L4 switch or a WCCP-compliant
router, is required.
trial period—Starting

with the first boot, the trial period provides 60 days of free
operation. All features are enabled during this time.

U
unicast alias—Defines

an name on the appliance for a streaming URL. When a
client requests the alias content on the appliance, the appliance uses the URL
specified in the unicast-alias command to request the content from the origin
streaming server.
universal time coordinates (UTC)—A ProxySG must know the current UTC time. By
default, the appliance attempts to connect to a Network Time Protocol (NTP)
server to acquire the UTC time. If the ProxySG cannot access any NTP servers,
you must manually set the UTC time.
URL filtering—See

content filtering.

URL rewrite rules—Rewrite

the URLs of client requests to acquire the streaming
content using the new URL. For example, when a client tries to access content on
www.mycompany.com, the ProxySG is actually receiving the content from the
server on 10.253.123.123. The client is unaware that mycompany.com is not
serving the content; however, the ProxySG access logs indicate the actual server
that provides the content.

W
WCCP—Web Cache Communication Protocol. Allows you to establish redirection
of the traffic that flows through routers.

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Volume 2: Proxies and Proxy Services

Web FTP—Web

FTP is used when a client connects in explicit mode using HTTP
and accesses an ftp:// URL. The ProxySG translates the HTTP request into an
FTP request for the OCS (if the content is not already cached), and then translates
the FTP response with the file contents into an HTTP response for the client.
Websense log type—A

Blue Coat proprietary log type that is compatible with the
Websense reporter tool.

X
XML responder—HTTP
XML requestor—XML

234

XML service that runs on an external server.

realm.

Index

A
About 15
active client connections 146
ADN optimization
attribute defined 30
Authenticate-401, attribute defined 29

B
bandwidth gain
additional configurations affecting 135
byte-range support 136
revalidate pragma-no-cache effects 138
bandwidth refresh, configuring 135
browser
proxy, configuring 214
setting for explicit proxies 215
bypass list, overview 49
byte-range support
bandwidth gain, affecting 136
configuring 138

C
CCLs
client certificates, specifying for 185
server certificates, specifying for SSL proxy
185
client consent certificates, using with SSL proxy
186
creating an HTTP proxy service 114

D
destination IP address
client
trusted, configuring 44
trusting 43
DNS
destination IP address, trusting 43
DNS proxy
overview 79
resolving name list, explained 79
resource record, creating 82

document, conventions 11
dynamic bypass
configuring 51
connection/receiving errors 51
dynamic_timeout value 51
lists, understanding 50
max_dynamic_bypass_entry parameter 51
server_bypass_threshold parameter 51
troubleshooting 50
dynamic_timeout value, using with dynamic
bypass 51

E
early intercept defined 29
editing an HTTP proxy service 114
explicit proxy
browser settings 215
creating 214
Internet Explorer, using with 149
overview 213
ProxySG, using as proxy server 214
explicit TCP-Tunnel, explained 207

F
FTP
clients, configuring 108
FTP proxy
configuring 101

H
hardware models, licensing 45
HTTP object caching policy, configuring global
defaults 123
HTTP object caching policy, customizing 119
HTTP object types 121
HTTP proxy
about 113
bandwidth gain profile 128
bandwidth gain, fine-tuning 135
byte-range support 136
normal profile 128

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Volume 2: Proxies and Proxy Services

portal profile 128
pragma-no-cache, revalidating 138
profile settings
configuring 133
explained 129
supporting IWA authentication for an explicit
proxy 149
tolerant request parsing 122
HTTP proxy profile, configuring 133
HTTPS
origination 156
HTTPS console
creating 19
enabling 19
IP address, selecting 19
keyring, selecting 18
managing 19
HTTPS traffic, intercepting 181

I
intercepting all IPs on port 80 113
Internet Explorer, explicit proxy, using with 149
IP forwarding, enabling 217
issuer certificates, downloading for desktops 186
IWA
explicit proxy,Internet Explorer, using with
149
Internet Explorer, using with 149

L
license
hardware models, limits 45
user limits, managing 44

M
Management Console
managing 15
SSH
client keypairs, importing 23
configuring 21
Telnet console 24
max_dynamic_bypass_entry, using with
dynamic bypass 51
meta tags, about 122
multiple listeners, best match 30

236

O
Object pipelining, about 120
objects, served 145
origination, HTTPS 156

P
PAC file, defined 214
Permeo
customer ID, obtaining 172
PA client, about 172
PA license, disabling on ProxySG 173
PA limitations 173
ProxySG, PA licensing 173
policy
bypass list 50
port services
attributes 29
HTTPS console, creating 19
supported 15
Telnet console, creating 24
prompt, customizing for Telnet 165
protocol detection 32
proxies
definition 11, 27
explicit, browser settings 215
explicit, creating 214
interface settings 215
SOCKS, configuring 170
proxies, understanding 213
proxy server, using ProxySG as 214
proxy services, best-match algorithm 30
proxy-support header
disabling through CPL 150
disabling through VPM 149
Internet Explorer, using with 149

R
realm banner, Telnet, customizing 165
reflect client IP address
client
reflect IP 43
refresh bandwidth, configuring 135
resolving name list, explained 79
restricted intercept
CLI, using 54
understanding 53

Index

revalidate pragma-no-cache
bandwidth gain, using with 138
configuring 138
routing
bypass list 49
policy-based bypass list 50

S
server_bypass_threshold, dynamic bypass,
using with 51
shell proxies
boundary conditions for 161
policy settings, customizing 160
See alsoTelnet
Telnet 161
understanding 159
SOCKS
compression gain statistics 175
connections, viewing 175
SOCKS clients, viewing 174
statistics 174
SOCKS proxy
bind timeout on accept value 171
configuring 170
connection timeout values 171
max-connection values 171
max-idle-timeout value 171
min-idle-timeout 171
SSH
client
keypairs , importing 23
managing 22
configuring 21
SSH host
welcome banner, creating 22
SSL proxy
Add Server Certificate object, configuring 191
Add SSL Forward Proxy object, configuring
190
categorizing hostnames in server certificates
192
CCLs for client certificates 185
CCLs, specifying for 185
client consent certificates, using 186
explicit mode, configuring 184
HTTPS

content, intercepting 190
traffic, intercepting 181
issuer certificates for desktops, downloading
186
rules, configuring 190
Server Certificate Category object, using 192
Set Server Certificate Validation object, using
193
SSL Access layer, using 192
SSL Intercept layer
configuring through CPL 194
using 190
statistics
unintercepted SSL byte 198
unintercepted SSL client 198
unintercepted SSL data 197
transparent mode, configuring 182
understanding 177
statistics
active client connections 146
client/server compression gain 147
HTTP/FTP bytes served 146
objects served 145
SOCKS clients, viewing 174
SSL proxy
unintercepted SSL bytes 198
unintercepted SSL clients 198
unintercepted SSL data 197

T
TCP-Tunnel
commands, explicit 211
explicit 207
overview 207
Telnet
banner settings, configuring 165
proxy boundary conditions 166
settings, customizing 165
shell proxy
understanding 161
Telnet console
error message 24
port service, explained 24
troubleshooting 24
tolerant request parsing, setting through CLI 122
transparent proxy

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Volume 2: Proxies and Proxy Services

hardware, configuring 216
IP forwarding 217
IP forwarding, enabling 218
Layer-4 switch, using with 217
overview 213
troubleshooting
Telnet console 24
trust destination IP
configuring behavior 47

U
user license limits

238

behavior if exceeded 45
concurrent users, viewing 47
configuring behavior 47
license metrics, viewing 46
managing 44
notifications, setting 46

W
Web FTP
configuring IE 6.0 118
welcome banner, creating 22
welcome banner, Telnet, customizing for 165

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