Implementing a Reverse Proxy | Blue Coat Systems, Inc.

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Posted May 16th, 2008 by snelson@bulldog...

Implementing a Reverse Proxy

What is a reverse proxy?

The Blue Coat ProxySG provides the basis for a robust and flexible Web communications solution. In addition to Web policy management, content filtering, blocking, web content virusscanning and network protection, companies can implement what is known as a reverse proxy to front end their Web applications. Implementing a reverse proxy with a ProxySG has the following advantages:

The ProxySG terminates the session with the client and establishes another session with the Web server
The Web server only sees the IP address of the ProxySG
An administrator can implement granular policies with authentication, authorization and logging
A company can achieve higher performance benefits with caching

A ProxySG with flexible advanced forwarding architecture coupled with caching provides organizations a best of breed solution to leverage their network.

Implementing a reverse proxy solution with Blue Coat

Reverse proxy with the Blue Coat ProxySG provides flexibility to network administrators in defining scalable proxy hierarchy designs. The following key features can be implemented:

Forwarding to an upstream Web Server
Load balancing of multiple Web Servers
L3, L4 and L7 health checks of the upstream Web Servers

There are three steps to implement Advanced Forwarding for each of these designs:

Configure Advanced Forwarding hosts
Configure Advanced Forwarding rules
Test the configuration

The following diagram presents the network layout of this solution:

Step 1 – Configuring Advanced Forwarding Host

To install the advanced forwarding configuration, open the web GUI interface on the ProxySG.

Go to Configuration | Forwarding | Forwarding Hosts

Click on install for "Install Local File from: Text Editor"

Into the text editor, paste the configuration:

Fwd_host <webserveralias> <ip_address or hostname of the web server> http=<server port> server

Step 2 – Configure Advanced Forwarding rules

The advanced forwarding rules are implemented via the Visual Policy Manager.

Open the Visual Policy Manager

Create a Forwarding Layer called "forwarding"

Then, create a rule with the following attributes and shown in the following screens:

   Source= any
   Destination = url=www.foo.com (what users will type in their browsers ie url seen by users)
   Service = any
   Action = Select Forwarding
   Time = any
   Tracking = none

Click on OK.

Click OK twice.

Finally, click on Install Policy

In this example the local ProxySG is 195.149.44.49 and the web server www.server.com is 195.149.44.201.

All requests not in cache for www.foo.com will be forwarded to the web server at 195.149.44.201.

Step 3 – Test your configuration

To validate that Reverse Proxy is working, enable URL logging

Blue Coat Management GUI | Access Logging Category | Default Facility | check Main facility

Look at the Security Appliance’s current logs

Blue Coat Statistics GUI | Access Logging category | Log Facility tab | Select Main

Observe the last couple entries so you can recognize the fields

DEFAULT_PARENT/WebserverIPAddress

Copyright © 2007 Blue Coat Systems, Inc. All rights reserved worldwide. No part of this document may be reproduced by any means nor translated to any electronic medium without the written consent of Blue Coat Systems, Inc. Specifications are subject to change without notice. Information contained in this document is believed to be accurate and reliable, however, Blue Coat Systems, Inc. assumes no responsibility for its use, Blue Coat is a registered trademark of Blue Coat Systems, Inc. in the U.S. and worldwide. All other trademarks mentioned in this document are the property of their respective owners. v.TP-AAA-v1-1007