When 18.104.22.168 is used, some Xbox Live features work, but some don’t. In particular, attempting multiplayer on Halo Master Chief Collection for PC doesn’t appear to work; any time players try to join each other, they get “failed to connect” errors in-game. Additionally, features that require Xbox Live, such as rankings, don’t show-up in game.
Switching to 22.214.171.124 resolves the issue.
I haven’t had time to troubleshoot much, but I’m guessing it’s an ECS issue. I don’t know which domains it’s querying; the networking for Halo and Xbox Live is a mess, so I’ll need a good chunk of time to figure it out.