As mentioned in the news, HLP and GameWarden will be moving to a new server in the very near future. Since FS2NetD was being hosted on the same server as those two, it'll have to move as well. As taylor is currently busy with Real Life
TM, there may be a slight delay until it is online again. Until then, you can arrange Multiplayer games via the Hard Light IRC channel, and use direct IP games.
FUBAR's standalone servers can be reached at the following IPs:
Standard: 75.32.154.228
FSPort: 75.32.154.227
MVP: 75.36.28.148
TBP: 75.32.154.227:7809
Simply enter these IPs in the appropriate box in the multiplayer options, turn off PXO, and they should be showing up in-game.