In this article he attempts to give a comprehensive overview of the proxying and mod_proxy_html This article was originally published at Apache Week in January 2004, and moved to Apache Tutor with minor updates in October 2006.
The current revision was made in October 2009 and incorporates updates in Apache 2.2 and mod_proxy_html 3.1.
The proxied server may be a webserver itself, or it may be an application server using a different protocol, or an application server with just rudimentary HTTP that needs to be shielded from the web at large.
The web agent acts as a filter for requests directed to the proxy server.
The web agent will intercept all requests directed to the web server where it is loaded and will communicate with Site Minder to determine if the requested resource is protected.
In 2003, Nick Kew released a new module that complements Apache's mod_proxy and is essential for reverse-proxying.
Since then he gets regular questions and requests for help on proxying with Apache.
Proxies are typically operated by ISPs and network administrators, and serve several purposes: for example, A reverse proxy is a gateway for servers, and enables one web server to provide content from another transparently.
As with a standard proxy, a reverse proxy may serve to improve performance of the web by caching; this is a simple way to mirror a website.
You may want to add it if you are concerned about the load on your network or origin servers, but the details are outside the scope of this article.
I'm also going to ignore all non-HTTP protocols, and load balancing.
If you are using an older Apache version, it is strongly recommended you upgrade.
For users of Unix-family platforms, you have a choice of MPM.
The Funda of Reverse Proxy - The web server will service any HTTP or HTTPS requests and CAN operate in reverse proxy mode.