Using a PAC file
A PAC file is a JavaScript function definition that a browser calls to determine how requests are handled. Clients must specify in their browser settings the URL from which the PAC file is loaded.
You can store a PAC file on the proxy and provide the URL for this file to your clients.
Note:
The PAC file can reside on any server in your network. Small networks may store the file on the proxy itself, but large, enterprise-class networks should use a separate server for storing the PAC file.
If the HTTPS protocol option is enabled, see Enabling SSL support for information about a PAC file to use with HTTPS traffic.