For future readers,
After an hour of troubleshooting, Dukelage and I managed to get a 2 hour game going which ended with us pretty much being bottled in by the AI.
Here are the things we had to do.
1. Because Duke and I had GOG versions, but different OS versions, we could not use the GOG direct connect method. If that is available to you, I think that may be a good and easy choice.
2. We went for the Direct IP litenet connection method. To get this to work, you would have to set up port forwarding on your router. Typically, you open a browser and type in the address to your browser, which typically begins with 192.168.foo.foo .
3. Once in router, check documentation to set up port forwarding. I ran into the issue where there were two places to do it, but the one that worked was the port forwarding in the firewall.
4. Select the IP of the computer you are playing AI war on (not your smart tv, not your ps3, haha), and select UDP, and select the port you use for AI war which you set in game under settings->networking. The default is 32340, but you can switch this around.
5. I had to roll back to an earlier version. VERSIONS must match. In our case, the linux releases were slower, but thankfully GoG Galaxy allows an easy roll back.
6. After that go in game host the game, then provide your public IP address to your fellow player. This can be found when you host a game, or in Settings-> Networking.
7. Your fellow human freedom fighters then on their side selects Multiplayer-> join and provide that IP.
8. Duke had to mess with settings due to a bug in the GOG release that made it seem like he was on an even older version than the one we were targeting after rollback. You may have to do this too.
9. Once in game, be aware that the lobby chat window is bugged, and cannot scroll. Keep chatter to a minimum so you can coordinate settings and when to start.
10. Enjoy! Performance was great on my side, but Duke ran into a couple of lags in the two hour game.
Bonus: We messed with Hamachi, but Hamachi does not seem to work on linux. But what we did allowed a cross OS game and it worked great. I believe this can do cross platform with Steamer friends as well. So get into a Giant clusterfoul with everyone you can find and kill those silicon overlords.
I hope this post helps future players. Leave a message here, I am looking for more allies to play with. How this was not in the Wiki or anywhere boggles me. I think me and Duke were both pretty technically savvy and it took us a full hour of troubleshooting due to false starts.
