What is a proxy server?

Proxy servers come in many types, but the two most common types are web proxies and anonymizing proxies.  Web proxy servers are servers used to cache webpages and provide access control for website content.  Anonymizing proxy servers do not reveal information about the client machine.

Proxy servers usually initiate connections to the internet on behalf of the client machine.  A client machine will send a message to a proxy server requesting specific information from a web server, and the proxy server will then search for and find that information then download it and send the information back to the client machine.  The proxy server does all the work for establishing and maintaining communication between the client machine and the web server.