Nginx proxy to Apache - access remote host IP address using mod_praf

These days it i getting more and more common for people to use a lightweight webserver such as lighttpd or nginx as a frontend, and proxy to an Apache backend if they really need to.

There is however a small problem when using Apache as a backend, as it will see all requests as originating from localhost (127.0.0.1). So, if you need access to the users real IP address in your application, you will need to install the mod_praf apache module and configure Apache to use the and X-Real-IP headers that gets sent by nginx.

First, set up a name based apache virtual host listening on port 8080:

NameVirtualHost *:8080
<VirtualHost *:8080>
  ServerName mydomain.com
  ServerAdmin me@mydomain.com
 
  DirectoryIndex index.php container.php index.html
  DocumentRoot /path/to/web/root/
  <Directory /path/to/web/root/>
    Options FollowSymLinks MultiViews
    AllowOverride None
    Order allow,deny
    allow from all
  </Directory>
</VirtualHost>

Tell nginx to listen on port 80 and proxy all requests to Apache:

server {
  listen 80;
  server_name mydomain.com;
    location / {
      access_log off;
      proxy_pass http://mydomain.com:8080;
      proxy_set_header X-Real-IP $remote_addr;
      proxy_set_header Host $host;
      proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    }
}

Install mod_praf:

sudo aptitude install libapache2-mod-rpaf

Then configure mod_praf by adding the following to your Apache virtual host:

RPAFenable On
RPAFsethostname On
RPAFproxy_ips 127.0.0.1

Restart apache:

sudo apache2ctl restart

And that's it. Apache should now have access to the original host IP address. Check your access logs for confirmation.