Ubisoft have decided not to support Far Cry 3 with dedicated servers according to a community manager on the official message board
"Far Cry 3's online experience does not support dedicated servers".
This naturally caused some commotion and gamers accused Ubisoft of trying to kill of the PC community for the upcoming game.
"Of course we are not trying to kill the PC community. We have simply decided on a different way of handling multiplayer. We weighed the different options against each other to see what worked best, and what we came up with worked very well even without DS's dedicated servers."