What's New in Apache Web Server 2.2?

Proxying

In addition to being divided from the caching modules, mod_proxy has undergone a number of other significant changes in 2.2.

Most importantly, the proxy features have been split into different modules to handle the various different protocols. Now, in addition to mod_proxy, there is also mod_proxy_http, mod_proxy_ftp, mod_proxy_ajp, mod_proxy_balancer, and mod_proxy_connect. Thus, when you want to enable proxying, you’ll need to enable mod_proxy, as well as the particular module that handles the particular protocol or feature you wish to enable.

mod_proxy can also work in conjunction with mod_cache to cache proxied content, or with mod_ssl to proxy content to an SSL/TLS server, using the SSLProxy* directives.

Forward and Reverse Proxies

Although it is slightly outside the scope of this document, a brief word may be warranted about the difference between forward and reverse proxies, so that the use of the terms is clear.

A forward proxy refers to a configuration where the client browser makes outbound connections via the proxy server. That is, the browser itself is configured with a proxy server. Each time it makes a request for a URL, it will send that request not to the target server, but to the proxy server, which will then make the request on behalf of the client, and return the response to the client.

A forward proxy configuration is typically done for security reasons or for performance reasons (or both).

For example, a forward proxy configuration might look like the following ...