Apache: extensionless URLs get an automatic .php extension

When I ask the server for an URL which has no extension, but is not a directory, apache automatically adds a .php extension to it. Where is this behavior configured?

EDIT: I'm sorry, my question wasn't clear: I'm not asking how to do this, I just found out that my local server (Apache/2.2.11 on Debian) does it by itself (i.e. I have no rewrite rules) and I wanted to know where this can be configured.

Solution 1:

Debian (speaking current versions as you mention Apache 2.2.11 which falls somewhere between Lenny and Sid) has the MultiViews option enabled for /var/www and /usr/share/doc directories by default in /etc/apache2/sites-enabled/000-default. With this option enabled Apache will attempt to match a URI request to any file with an extension it knows about. That said if the URI is requesting /test it will attempt things like test.php, test.html, test.txt, etc until it finds a match.