A proxy server is an intermediate program or computer used when navigating through different networks of the Internet. They facilitate access to content on the World Wide Web. A proxy intercepts requests and serves back responses; it may forward the requests, or not (for example in the case of a cache), and it may modify it (for example changing its headers, at the boundary between two networks).
A proxy can be on the user's local computer, or anywhere between the user's computer and an destination server on the Internet. In general there are two main types of proxy servers:
- A forward proxy that handles requests from and to anywhere on the Internet.
- A reverse proxy taking requests from the Internet and forwarding them to servers in an internal network.