Since Diaspora multiplayer is currently in beta, playing it won't be as polished as the singleplayer experience unfortunately. So here's a step by step guide on how to get the beta running.
1) (Optional). Register on FS2NetD
, Diaspora's matchmaking service. You don't need to do this for a LAN game.
2) If you want to host, you'll need to forward ports 7808 and 7117 (TCP and UDP) on your router or firewall. Step 4 here
shows how to do this for other FS2_Open games and the procedure is the same for Diaspora.
3) In the Diaspora launcher's Basic Settings tab, make sure that the network connection type is set to Broadband/LAN and that the connection speed is set to Cable/LAN. Ignore the two Force options. In the advanced tab, add this to the Custom Flags section
4) Run the game and create a multiplayer pilot.
5) (Optional) If you want to play over the internet as opposed to on a LAN, go to the Options screen (F2) and then select Multi. Make sure the button marked PXO is selected then add the username and password you created in step 1. You may wish to change the Object Update settings here depending on if you are hosting or not. Reports say that clients should be on Low while the host should be on High.
6) Go to Briefing and you'll find yourself in the lobby where you can chat to other players.
7) Click on games and you'll be presented with a list of currently running (or forming) games. You can only join games while they are forming at the moment, not while they are running. If you wish to host a game, click on Create Game and you'll be taken to the setup screen. Otherwise, simply join a game.
8) Diaspora can also be run as a standalone server on Windows by setting the run as standalone server option in the launcher's Advanced Settings.
The Diaspora team hope that players will still enjoy multiplayer despite the (minor) complexity of getting started. We will of course try to improve things for the later releases but in the end we decided that many of you would rather have a work in progress version of multiplayer to play with, than no multiplayer at all.