rpaf changes the remote address of the client on incoming proxy requests. It is used in backend servers that needs to know the IP of the client, and works in conjunction with mod_proxy_add_forward (which sets the X-Forwarded-For header). When an X-Host header exists rpaf will take the hostname found here, put it into Apache, and update the virtualhost settings so that you can serve virtualhosts on the backend. It includes modules for both Apache 1.3 and 2.0. License: The Apache License Changes:
The ability to change which header Apache looks at was added. With the configuration directive RPAFheader, you can now change the default X-Forwarded-For to X-Real-IP if you so choose. There are also bugfixes in this version that makes mod_rpaf work correctly with Keep-Alive requests.