I'm unable to find this information specified somewhere.
Basically, the Borderlands version purchaseable through the Mac App Store, can it play with Borderlands installations running on Windows, ie. co-op, etc.?
Or can Mac version only play with Mac, and same for Windows version?
Best Answer
Steps:
GameRanger basically sets up a VPN connection between the parties involved, then connects the players via the LAN Game function. So it can be pretty tricky to get working with various routers, ports, firewalls, etc.
Source: http://forums.gearboxsoftware.com/showthread.php?t=117273