Warcraft II together in ONE WLAN?


Is it possible to play Warcraft II via Battle.net (login through the GOG client) with two player accounts and corresponding licenses in the same WLAN? I want to play Warcraft II against my brother at home, specifically in the same WLAN.

Here’s what I have already tried:

  • I have purchased two licenses of Warcraft II, and both work correctly. I can log in to Battle.net with both profiles and create multiplayer games.
  • On both Macs where Warcraft II and GOG are installed (in Parallels Desktop mode), I can log in with both profiles and access the Battle.net platform.
  • When I log in to Battle.net on one of the two Macs connected to the same WLAN with one of the profiles, the second Mac with the other profile cannot access the platform. The error message states: “Your internet connection is either very poor or does not handle UDP packets over port 6112. You can chat but cannot play. Contact your internet service provider or system administrator for help opening the port.”
  • I have also tried using a second network on my router with one of the Macs, but that didn’t work (the same error message appeared).
  • Connecting one of the Macs to my mobile hotspot and using the 5G network doesn’t work either. I can’t even access the platform.

It’s not a general login problem as the router allows the required ports. The question is whether only port 6112 is used in general and if it is locked by the first computer in a network, preventing the second computer from logging in through this port. Alternatively, can the second computer be configured to use a different port like 6113, allowing both computers to log in and play against each other in the same network?

How can I solve this problem? Thank you very much for your response. Best regards, BT19