brunodada says it did not work for him.
brunodada dice que no le sirvio.
Keep in mind that not Ultrasurf is being blocked, but the user trying to use that service.
In other words, if you have a client on your network say 192.168.1.20 who is trying to use Ultrasurf, he will be denied all network access for x amount of time.
That said, after reading on the fail2ban homepage, this kind of blocking is mainly used to block attackers from the outside, not so much from the local network.
This method MAY be used to deny access to Facebook, Ultrasurf, Windows Live and other services, but it's like punishing users for their bad habits.
Cheers.