Oh, that kind of TCP hole punching. No, we don't do that, because we run over UDP only. So far, I don't think we've seen network conditions where UDP is blocked

Oh, that kind of TCP hole punching. No, we don't do that, because we run over UDP only. So far, I don't think we've seen network conditions where UDP is blocked but the NAT is friendly enough to permit TCP traversal (same problems as UDP traversal, only with extra state to manage). I suppose we might get to it eventually, but there's a lot of simpler cases we can handle better first :)