- last post: 01.01.0001 12:00 AM PDT
Here you go.
(from http://support.microsoft.com/kb/829473)
Port listing
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.
Each time that you join or create an Internet multiplayer game, Halo automatically checks the Internet for the latest Halo update. You can also run the stand-alone updating tool, Haloupdate.exe, from the root of the folder where Halo is installed. (For example, you might use this tool to run the check in batch mode.) Halo uses HTTP to look for updates.
To verify that these ports are open or to open these ports, ask your network administrator or contact your Internet service provider (ISP). If you are the administrator of the network, see the documentation for your networking software or hardware to determine the steps to open these ports.
You can change the host and client ports if you have to customize Halo to work on your network. If your network is configured so that the default port range does not work, you must set the ports to values that you know will work. To customize the host and client ports for your network, follow these steps: 1. Start Halo.
2. Click Profiles.
3. Select the profile that you want to change network settings for.
4. Click OK.
5. Click Settings, and then click Network Setup.
6. Click Host Port or Client Port, and then type the correct number.
7. Click OK.
For more information, see the second article link in the "References" section of this article.
You can play Halo games from behind most routers and NAT devices. If you have difficulty connecting from behind a router, review your router documentation to make sure that the host and client ports are not blocked for your computer.
If you can't understand what to do, ask a friend, and I'm sure they can help more. And also make sure you have a good internet connection and your computer's graphics can run Halo smoothly if you want to host, or else everyone will lag.
[Edited on 08.28.2007 12:26 PM PDT]