A proxy server is a server that forwards requests to other servers for its clients,
when talking about computer networks. It is either a computer system or an application program.
The proxy server allows the client to connect and request files, connections, web pages, or other resources,
from a different server. The proxy server connects to the specified server, requests the service as the client,
and then provides the resource. Sometimes, proxy servers can change the server's response or the client's
request, or it can even serve the request without needing to contact any server at all. That means that
it would save, or cache, the initial request to the specified server, and use it later, to make everything
quick and smooth.
A tunneling proxy, or gateway, is a proxy server that passes every request or reply unmodified. It can be placed at certain key points in between the destination servers and the user, or on the user's computer itself.