https://bugs.winehq.org/show_bug.cgi?id=42127
--- Comment #2 from Sebastian Lackner sebastian@fds-team.de --- (In reply to Adam Martin from comment #1)
Never mind; I realised that I wasn't running the game in offline mode. Everything works fine when I'm offline. :)
Multiplayer should work fine in Wine Staging 2.0-rc3. Could you test if the problem really has been fixed in the meantime? If not it would be misleading to mark it as FIXED. Doom works without offline mode on Windows - if it behaves different under Wine there is still a bug.