This site is being deprecated.
Please see the official X‑Plane Support page for help.
X-Plane 10's default multiplayer only works on local networks, for examples computers on the same wifi network. VATSIM and PilotEdge are a couple third party mulitplayer servers. X-Plane is not integrated with Steam mulitplayer functionality (this article for more info).
This site is no longer being actively maintained.