We've been receiving a lot of inquiries from people concerned about recent allegations that Comcast is interfering with its subscribers' use of the BitTorrent protocol, perhaps by using an appliance that disrupts BitTorrent sessions. Some of the people contacting us are Comcast subscribers who've had trouble with BitTorrent recently and think that they might be affected by the same problem.
Debugging network problems can be complicated because of the varieties of versions and configurations of client software and the number of places in the network where problems could occur. Most mysterious network errors aren't intentionally caused by anyone. But some ISPs and universities have experimented with appliances that block or disrupt particular traffic, such as VoIP or P2P file-sharing traffic.
On Wednesday, we spoke with Comcast to try to find out what was going on in this case. Comcast assured us that, while it does do some kinds of network management on its residential network, it isn't deliberately blocking, degrading, interfering with, or discriminating against particular protocols or kinds of traffic. (This is consistent with what Comcast told the press in August when these allegations were widely raised.) The company said that it isn't using network management techniques that are designed to disrupt anyone's use of BitTorrent (or any other application).
If anyone has repeatable indications that something else is going on, please let us know -- we'd be happy to bring it up with Comcast to try to get to the bottom of the situation.