Yes, Sierra pulled the plug on the old master server. It is high time for lithfaq.com, the home of the new master server! To continue playing AvP2 just as you played it before this day, you'll only need to download and install this particular modification:
That screenshot was taken minutes ago. Our project was a success. Although there are still things to be improved, we have acheived our goal, to allow players to continue playing the game as they used to. AvP2 gets to live past this day.