You can specify which proxy servers your users connect to. A proxy server acts as a security barrier between your internal network (intranet) and the Internet, keeping other people on the Internet from gaining access to confidential information on your internal network.
If you want to use proxy servers for any of the listed services, select Enable proxy settings.
Type the address of the proxy server to the right of any of the listed services. Type the port number, which in many cases is 80, in the appropriate boxes under Port number.
To use the same settings for all services, select Use the same proxy server for all addresses.
In certain cases, you may not want to use a proxy server, such as for addresses on your corporate intranet. You can enter specific addresses in the box under Do not use proxy server for addresses beginning with. Use a semicolon to separate entries. To bypass proxy servers for all addresses on your intranet, select the Do not use proxy server for local (intranet) addresses check box.