With the recent shutdown of GameSpy, RA2 doesn't currently have a dedicated server for listing games in multiplayer. However, using the IP address should have worked... Regardless, as KOS has eluded to, most people use gameranger or hamachi.
If there is enough interest, I might be able to get RA2 to use GTM's servers instead of GameSpy's nonexistent servers for listing active games. Assuming my preliminary tests are accurate, it shouldn't take more than a few hours to get something up and running. The drawback is that I would probably need to do a manual edit to the EXE because I'm not sure that sergepatcher would support something like this. The benefit, however, is that I could potentially show this list outside of RA2 and external software wouldn't be necessary for users to find a game.
