Reverse Proxy in Ubuntu

The last few days I have spend some time setting up 2 new servers. One running Railo on Ubuntu and the other Coldfusion in Windows. I needed to host this on a single IP address and needed both machines available on the internet. There are 2 ways I know of that can accomplish this task 1. Using Microsoft ISA and 2 Using Apache as a reverse proxy. As I already have Apache up and running I went with option 2. While a seemingly trivial task I had never done this before and got hung up a few times the following are the steps I took:

Define the urls you want to re-direct to a different server:

  ServerName www.myExternalDoomianName.com
  ProxyPass / http://myInternalDnsName/    ( or ip address )
  ProxyPassReverse / http:// myInternalDnsName /  (or ip address )
  ProxyPreserveHost on

ProxyPreserveHost keeps the host headers intact so the internal sever can still use virtual websites.
Enable the site ( debian/ubuntu specific )

A2ensite myReverseProxySites

Need some extra bits for apache:

apt-get install libapache2-mod-proxy-html
a2enmod proxy
a2enmod proxy_html
a2enmod headers
a2enmod proxy_connect
a2enmod proxy_balancer

Restart apache

/etc/init.d/apache2 restart

If something isn’t working start looking in the logs:

tail -f  /var/log/apache2/error.log