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 a 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.