I know that The following DirectPlay ports must be open for you to play a game over a local area network (LAN), to play a direct Internet multiplayer game, or to play a game through GameSpy Internet Matchmaking:
•80 (Transmission Control Protocol [TCP]) - Halo looks to see if there is a Halo update available. If there is an update, Halo downloads the update through this port.
•2302 (User Datagram Protocol [UDP]) - the game host listens on this port.
2303 (UDP) - the game client connects to the game host through this port.
But how exactly do I open those ports, I am trying to host a server on Halo Custom Edition for fun. And apparently all of my friends say it says attempting to reconnect to the server, or retrying server... (1), (2) etc;
And needed some help on opening those specific ports 2302 and 2303.