Accessing the Apache Server

[trunning]

I am a newbie to Ubunutu. I have setup Ubuntu LAMP Server. I can access the Apache Web Server default page internall on my network. However when i tried to access it from outside my network, I get a page that says it cannot be reached. I have already setup domain name forwarding and made the changes on my router to redirect that domain name to my internal server.

TIA,

Trunning