Let me take a wild guess. /etc/hosts resolves your hostname to a loopback
address, like 127.0.1.1 or somesuch.

If that's the case, please change /etc/hosts to make your hostname resolve to
your network card's IP address.

If that's not the case, please attach a +winsock log to bug 9787.

+winsock,+sync please.
Another wild guess: maybe some out game update or something was recently rolled out?