Server not on list

I think I may be missing a port that needs to be forwarded. People can connect to the server just fine, but they can only join by clicking on my name on their friends list (they can also connect via console using the connect command). I forwarded the basic ports, 27015 UDP and 1200 TCP/UDP. Portforward.com told me the ports that were needed, although they did not allow my server to appear on the list. Any suggestions for ports or any general help is appreciated.

I’ve had the problem for a while, it goes away when the server has been on for a long time… It’s weird, but it’ll fix itself.

Thanks, but my server doesn’t appear on the list at all. I’m almost certain that I’m missing a port for the server list. If you know the correct port for the server to appear on the master server list, please tell me, as I might have forwarded the wrong ports.