Apache‘s reverse proxy is an act of an Apache webserver providing content from other webserver transparently. This is useful in many instances such as caching and mirroring, but it’s mostly used to serve websites that are hosted behind NAT or a firewall. A reverse proxy server routes connection addressed to the internal server, and the client sees the reverse proxy server itself as the origin server.

For example, Apache can be configured to serve URL‘s such as http://www.example.com/webapp to actually get the content from, which is hosted from an internal network. This happens transparently and the user initially requesting http://www.example.com/webapp need not to be aware of what happens in the background.