Update: The Mac and Windows versions of Borderlands 2 are back in sync and can play cross-platform! At this time we do not have an ETA for Linux. Thank you for your patience.
The latest update on the Windows version of Borderlands 2 has temporarily disabled cross-play for Linux. Currently, Linux players are unable to connect with Windows and Mac players.
We are working on an update to bring Borderlands 2 back in sync, but we do not currently have an ETA for release. We encourage players to join our #Borderlands Discord Channel to coordinate co-op matches with other Linux players, as we work towards delivering the update to re-enable cross-platform play with Windows and Mac players.