A proxy server is a application running on a computer connected to the internet that allows other computers to connect to it, and reach the Internet under the identity of the proxy server.

A proxy server is generally used in an office to allow the computers in that office to share the same Internet connection. The proxy server also has the ability to monitor what the employee's are doing on the Internet, and to block certain Internet Sites.

Misconfigured Proxy Servers are also used by hackers and spammers to hide their identities on the Internet.