Proxying with Apache
The standard Apache module mod_proxy supports both types of proxy
operation. Under Apache 1.x, mod_proxy only supported HTTP/1.0, but
from Apache 2.0, it supports HTTP/1.1. This distinction is
particularly important in a proxy, because one of the most significant
changes between the two protocol versions is that HTTP/1.1 introduces
rich new cache control mechanisms.
This article deals with running a reverse proxy with Apache 2. Users
of earlier versions of Apache are encouraged to upgrade and take
advantage of the altogether richer architecture and improved
application support. At the time of writing, the reason most commonly
cited for not upgrading is difficulties running PHP on Apache 2. I
cannot speak from personal experience, but several well-informed
sources tell me the difficulty lies with non-thread-safe code in PHP,
and that it works well with Apache 2 if it is built with the
non-threaded Prefork MPM.
