Cannot access wordpress behind a firewall

Hi,

I installed centos 6.3 and Apache, The centos server also runs php and mysql. Everything went fine. I uploaded a new wordpress installation went throuh the installation process and i can access it on the localhost without a glimp. Also I set the home and site url on http://www.mydomain.nl and i can access it without any problems on the localhost..

But when i try too access my site from externally i just cannot access it.. i have created the forwarding rules in my firewall and when i telnet my site i can access the web server without any problems.
I also created a hello world index.php as a test put it in the documentroot folder.. and now i CAN access the site from externally I have no clue and hope that you guys can help me too solve this problem with wordpress. I really need too access wordpress from externally..

p.s sorry for my bad English 😉