Server port in steam browser

[Chaduke]

What determines this port number in the steam browser?

When I run my server startup script I add -port 27015 but when I look at my server in the steam browser it says its running on port 62918.

I'd like to be able to advertise my server on my website but it wont work unless I can determine what the port number is going to be. When I try to search for it using only the IP address and no port in the steam browser it doesn't find it.

The port also changes when I restart the server. Any suggestions?

[Hollanda]

port forward

[Chaduke]

I understand what port forwarding is and how to do it but I don't understand how that answers my question.

EDIT : I think it may have something to do with my router's firmware.  I did some more searching and some claim this will fix the problem.

EDIT2: after installing the new firmware it still does the same thing. I'll have to keep searching for an answer.