Associated Press reporter Peter Svensson has discovered that internet service provider Comcast is blocking file sharing activities by its customers.
Svensson tested the thesis that Comcast blocked certain IP traffic by attempting to download the Bible—chosen because it has no copyright restrictions and was of a convenient size—using BitTorrent from Comcast-connected computers in San Francisco and Philadelphia. “In two out of three tries, the transfer was blocked,” writes Svensson. “In the third, the transfer started only after a 10-minute delay. When we tried to upload files that were in demand by a wider number of BitTorrent users, those connections were also blocked.”
Analysis of the failed transfer process on the San Francisco computer showed the failure was a result of reset packets. Reset packets tell the receiving computer to “hang up the phone.” According to Svensson, “traffic analyzer software running on each computer showed that neither computer actually sent the packets. That means they originated somewhere in between, with faked return addresses.”
Sandvine, a Canadian company that sells equipment capable of sending those reset packets, did not respond to Svensson’s request for comment and Comcast refused to confirm that it uses Sandvine equipment.
