What is a Proxy Server ?

In computer networks or internet, proxy server is a server (a computer system or an application software) which serves the requests of its clients by forwarding requests to other servers or sites. A client connects to the proxy server, requesting some service, such as a file, connection, web page, or other resource, available from a different server or website.

The proxy server provides the resource by connecting to the specified server and requesting the service on behalf of the client. A proxy server may optionally alter the client's request or the server's response, and sometimes it may serve the request without contacting the specified server. In this case, it would 'cache' the first request to the remote server, so it could save the information for later, and make everything as fast as possible.

A proxy server that passes all requests and commands and replies unchanged is called a gateway or tunneling proxy. A proxy server can be placed in the user's local personal computer or at specific locations between the client and the destination servers or the Internet network.