Can I use PAC (Proxy auto-configuration) files with WebMarshal?

This article applies to:

• WebMarshal 

Question:

• Do PAC files work with WebMarshal?
• How do I use or deploy PAC files with WebMarshal?

Reply:

Yes, you can use PAC files with the WebMarshal proxy. PAC files are applied at the web browser level, and do not depend on the proxy software.

Usage and configuration of PAC files will depend on your environment. Trustwave Technical Support is not responsible for authoring, reviewing or deploying PAC files.

The remainder of this article provides some general suggestions about usage and deployment of PAC files, and links to additional information.

PAC Usage:

Proxy Auto-configuration (PAC) files direct a browser to use specific proxy servers. Because PAC files are scripted, they can contain complex configuration such as:

• A list of URLs that should be excluded from proxying
• A list of one or more proxy server names (or IP addresses) and ports that can be used
• Different proxy server usage depending on the client IP address (useful for laptops that may be browsing from different networks)

PAC files can be hosted on each workstation, or on an intranet server. PAC files and browser configuration can be updated using Windows Group Policy or other administration tools.

Sample PAC Configuration

The procedure given below is for a PAC file in its simplest form and should work for any web proxy software. It redirects all website requests from a client computer's browser to the WebMarshal proxy server (just as would happen by entering proxy information directly in the browser).

• In the example, the name of the proxy server is webmarshal.local and the proxy port is the default 8080.
• Substitute the correct name or IP address and port for your WebMarshal proxy.  

1. Create a text file using Notepad.
2. Copy the script below into the file (replacing the name and port of the proxy server with the actual name or IP address and port of your WebMarshal server).
   • If you use a name, ensure that it can be resolved to an IPv4 address.
   
   
      function FindProxyForURL(url, host)
      {
         return "PROXY webmarshal.local:8080";
      }
   
   
3. Save the file as  C:\proxy.txt
   • For testing you can save this file in any convenient location that your account has read and write access to.
4. To use this file:
   • For Internet Explorer
     • Open Tools > Internet Options > Connections > LAN Settings
     • Select "Use automatic configuration script"
     • Enter the path as file://c:/proxy.txt (or the path where you saved the file). Note: the format is URL format with the "file" prefix.
     • Click OK as required to accept the changes.
   • For Firefox (recent versions)
     
     • On the Firefox menu open Options > Options > Network, and click Settings
     • Select "Automatic proxy configuration URL"
     • Enter the path as file://c:/proxy.txt (or the path where you saved the file). Note: the format is URL format with the "file" prefix.
     • Click OK as required to accept the changes.
   • For other browsers, please refer to their support documentation.
   • Note: Some browsers may require (or prefer) an additional / character in the file location specification, as follows: file:///c:/proxy.txt 
5. Browse to http://webmarshal.home and you should see the WebMarshal home page.
6. Browse to Internet sites. You should be able to see the activity from the specific computer in "Active sessions" within your WebMarshal Console.

Notes:

• For information about using the Web Proxy Auto-Discovery Protocol (WPAD) with WebMarshal, please visit Trustwave Knowledgebase article Q12228.

References:

http://en.wikipedia.org/wiki/Proxy_auto-config