How to run PHP4 and PHP 5 parallel

Tobias Schlitt wrote a summary about How to run PHP4 and PHP 5 parallel. I use this technique (with a hint by Rasmus long time ago) also for checking if new minor PHP versions run correctly before really going live.

And he didn’t mention the mod_proxy approach for delivering both over port 80.

The following line in your VirtualHost directives would serve the php5 based site running on port 85 from port 80, too.

ProxyPass /
ProxyPassReverse /

There are certainly less ressource hungry solutions to this problem, but for testing and having fun it’s certainly good enough.