Basically, to try to answer your question. If your running some kind of firewall that's blocking your ports, your off to a great start. Now opening it up a little to allow your game to work online is not so bad, because although the port is open, it's in use, and I'm gonna assume that the game is not gonna except any connections that are not from a game server you connected to. You should be resonably safe to play your game.
On the other hand, make sure that your game is up to date with the latest patch for the it.


--PuRe www.pureescape.net