I am trying to follow some instruction I found on reddit to allow me to get the multiplayer achievements in Halo 2 on PC.
I have multiple computers setup with vanilla Windows 10 and Halo 2 activated with a CD key. I have turned off the Windows firewall on both computers and have turned on all sharing options I can find.
I have a switch that is connected to my primary router via a regular ethernet cable and connected to each of the other computers via crossover ethernet cables (even though I feel like these aren't important I wanted to follow the reddit post closely). I have also tried swapping out the switch for a router which is running OpenWrt.
When I go in to the "Xbox guide" thing within the game I can see that my public and internal IPs are correct, and a "system link" address is displayed.
I am able to create, join, and play games under LAN, but if I create a lobby under the "Live" option and invite the other computer it will spend ~30 seconds trying to connect and then show "You can’t join this party because it is no longer available". This also happens when I "Join session" from the other computer, and it doesn't matter which computer is the host.
I'm at my wits end with this, especially since sourcing enough computers, installing Windows, installing Halo 2, getting the right networking together, etc. has taken a while, and I feel tantalisingly close!
Any help will be greatly appreciated!