Sep 4 '20
Right now from what I can remember, it's a medley of issues. Older MSN versions using legacy P2P methods that can't traverse through today's NAT-reliant connections, people's routers not allowing UPnP connections to take place or outright blocking the necessary traffic, Escargot servers not properly supporting the services needed to initiate a P2P session for WLM 8 and higher (for now, I hope). There's no one source and each case will have to be treated differently depending on the circumstances.
That being said, when the next wave of Escargot updates are finally out (probably getting tired of me mentioning that all the time, but rest assured that is going somewhere) I believe the WLM 8 traversal issues should be fixed, although that isn't certain until things are rolled out and made live so that can be properly tested. There's also the SpotLife gateway Billy mentioned that could be worth reimplementing, so long as time allows us to get to that, but I believe that only works up to version 7.5 of MSN Messenger. I also remember finding out through aMSN's source code that there was another voice/video-related SIP gateway which I don't remember many details on except that it was most likely used in the WLM 8 releases. Also worth implementing once time allows us. In the end though voice and video chat aren't an awfully large part of Messenger and we shouldn't kill ourselves too much over getting both working. Luckily webcam works in varying degrees of success for some people, so I guess just cross your fingers when using that (or port forward TCP and UDP port 5004 on both you and your contacts end, but I'm not so sure on that claim's credibility). :P