I just tried to connect with php to an other mysql server which runs on my localhost on an other port then the standard 3306. I used this syntax:

mysql_connect('localhost:3307', 'mysql_user', 'mysql_password');

But the damn php always connected to the default mysql server with port 3306.

After a lot of google searches I found the solution.

If you are using localhost as your mysql server, php always use the port 3306. It simply ignores this value.

Easy workaround, is that you use 127.0.0.1 with the new port.

mysql_connect('127.0.0.1:3307', 'mysql_user', 'mysql_password');

Btw: If sql safe-mode is turned on the server parameter is ignored. Ask your Hoster to change it, or to turn it off.