When a user asks for a page, the proxy server checks to see if it has the page. Organizations often use proxy servers as a firewall to allow users restricted access to the internet. The proxy server contacts remote sites and fetches pages on behalf of the clients. The standard web transfer protocol is called HTTP . HTTP requests can be simple or full.
Simple request is just a GET line naming the page desired without the protocol version.
The response is just the raw page, with no headers, no MIME, and no encoding. Full requests are indicated by the presence of the protocol version on the GET request line . It replaces the existing data. Appends the new data to the existing data on the server. Having one page point to another web page requires mechanisms for naming and locating pages.