Apache 2 Pocket Reference

Chapter 9. Proxying

The mod_proxy module adds multiprotocol proxy server capabilities to Apache, allowing documents to be fetched from other servers, which may themselves be proxy servers. As of Apache 2.1, mod_proxy provides facilities for connection pooling, and, as of 2.2, for load balancing. Caching functionality was moved out of mod_proxy in Apache 2.0 and is now provided by mod_cache.

Support for individual protocols is implemented by separate provider modules, as listed in Table 9-1. Proxying of content over SSL/TLS connections requires the support of the mod_ssl module.

Table 9-1. Proxy support modules

Module	Protocols supported
mod_proxy_ajp	Apache JServ Protocol version 1.3 (AJP13)
mod_proxy_balancer	Pseudoprotocol used for load balancer groups
mod_proxy_connect	HTTP CONNECT, used to tunnel SSL/TLS requests
mod_proxy_ftp	FTP (supports only GET requests)
mod_proxy_http	HTTP and proxied FTP

Basic Proxy Configuration

A request is deemed to be a proxy request if the hostname in the URL is not one served by the server. Requests can also be rewritten to be proxy requests using the RewriteRule directives with the [P] flag.

A proxy server can operate in two modes: as a forward proxy, where it accepts requests for remote URLs and fetches those resources on behalf of clients; or as a reverse proxy, where requests for URLs on the proxy server are mapped to remote URLs, retrieved, and returned to the clients as if they originated from the proxy server itself.

mod_proxy recognizes a number of environment ...