Geez, people don't get it. If you can't connect, use a different port (such as 8080, 80, 5190, etc) and find several hosts also using the port (or do it reverse, find clients using odd ports and set your port to the most popular one that isn't blocked by your firewall. The ones mentioned should be default as they have other uses and would never be banned. Too bad no one WANTS to change.