I have a chromebook running linux (ubuntu 14.something) and got Barotrauma running on it fine in single player (frames suck but that doesnt matter). My issue is that I cannot create or join a server. Not being able to create a server is caused in part because I have not set up any port forwarding, however I dont know why I cant join servers. Any help would be appreciated.

Yeah the game could still be requesting a port to be opened to even play on a online server. Have you tried using UPNP in the router settings & then trying to play online?
I would not leave UPNP on all the time but its sometime to try & see if the game runs with it on & what port is open for the game, etc.

Try this: Open the terminal, then run the game in window mode & try to host or join a server. Then go to your terminal window while the game is still running & type
That will show you what ports are open, etc

I believe the default port for Barotruma is 14242.

That still doesnt answer his question of he cant JOIN servers, my question is do you get an error message? because i get an error saying failed to start client Feature not implemented yet