JAVA VERSION
RE: Hosting
There are several TCP/IP ports that need to be open for
the game. The actual steps very from firewall/router to
firewall/router. I don't recommend putting a computer in the DMZ. One
can just redirect TCP/IP ports, so that only a few ports are actually open.

In general, there is usually a screen for opening or redirecting
requests to the host computer. The host should be the only one that
needs to make any modifications to firewalls. All connections are
initiated from the client.

TCP/IP 1975 -- This is for initial communication
TCP/IP 2075 to 2081 -- Commands (Requests for information from a player)
TCP/IP 2176 to 2182 -- Events (What an observer would see)
TCP/IP 1356 to 1362 -- IM Client

Note: Yahoo! Messenger, AOL IM, and Outlook sometimes open on these
ports. The solution is to just close Outlook, Yahoo!, or AIM and then
start again.