Hi, I have similar problems to GaskooN, I can connect fine to the net, the problem comes in where I try to play DotA 2 (and Call of Duty: Black Ops) I cannot connect to the valve hosted servers (not to spectate, play, or download replays).
What I have done so far is a Telkom adsl line-reset, as well as had the line test done by them, I have flushed my DNS cache, tried several different DNS servers, all unsuccessful. The problem only started yesterday (or the day before), and after the reset I had some connectivity to the servers for the while that I was still online, but today I have the same problem.
Any help would be appreciated.