What is a Proxy Server?

A proxy server manages traffic between your network and servers on the Internet, and determines whether network packets are allowed to pass through to the network. When a client computer makes a request, the proxy server translates the request and passes it on to the Internet. When a computer on the Internet responds, the proxy server passes the response back to the client computer.

Restricting Connections

You can configure a proxy server to block inbound connections in order to enable LAN clients to initiate connections to Internet servers, but also prevent Internet clients from initiating connections to LAN servers. You can also configure a proxy server to restrict outbound connections so that LAN clients are authenticated by using their standard security credentials.

You can restrict outbound connections in several ways-by user, program, protocol, TCP/UDP port number, time of day, domain name, or IP address.

Caching Information

Proxy servers typically cache information from the Internet. For example, if multiple users view the same Web page on the Internet, a proxy server can retrieve that page only once from the Internet, keep a copy of the page in its cache, and then forward the copy to all users. This reduces traffic between your intranet and the Internet because the proxy does not have to retrieve the Web page from the Internet separately for each user.