A proxy refers to a server that functions as an intermediary between a client work station and the Internet. It ensures administrative control and security. Furthermore, it enables the use of caching services for work stations in the network.
How does a proxy server work? Its function starts when a user sends a request for an Internet service, such as a request to access a Web page. Once the request passes the proxy’s filtering requirements, the proxy will check in its local cache if it has the requested Web page. The proxy’s local cache contains the pages previously downloaded by the server.
If the proxy has the requested page in its local cache, it will forward the page to the user’s work station. This is done without accessing the Internet.
If the proxy does not find the page in its local cache, the proxy will act as a client, and use one of its IP addresses to forward the page request to the main server. The main server will then find the page on the Internet. When the page is obtained, the proxy receives it and forwards it to the user who requested it. All this is done by the proxy while remaining invisible to the user.
A proxy associates with other servers in order to perform its functions. First, a proxy server is associated with a gateway server, which separates the network from external networks. Second, a proxy server is associated with a firewall. This application protects the network against unauthorized intrusions. There are applications that combine the functions of a proxy, a gateway, and a firewall in one interface.