The Uninspired Manifesto
Friday, August 17, 2007
Comcast Throttles BitTorrent Traffic
Over the past weeks more and more Comcast users started to notice that their BitTorrent transfers were cut off. Most users report a significant decrease in download speeds, and even worse, they are unable to seed their downloads. A nightmare for people who want to keep up a positive ratio at private trackers and for the speed of BitTorrent transfers in general.
ISPs have been throttling BitTorrent traffic for almost two years now. Most ISPs simply limit the available bandwidth for BitTorrent traffic, but Comcast takes it one step further, and prevents their customers from seeding. And Comcast is not alone in this, Canadian ISPs Cogeco and Rogers use similar methods on a smaller scale.
Unfortunately, these more aggressive throttling methods can’t be circumvented by simply enabling encryption in your BitTorrent client. It is reported that Comcast is using an application from Sandvine to throttle BitTorrent traffic. Sandvine breaks every (seed) connection with new peers after a few seconds if it’s not a Comcast user. This makes it virtually impossible to seed a file, especially in small swarms without any Comcast users. Some users report that they can still connect to a few peers, but most of the Comcast customers see a significant drop in their upload speed.
The throttling works like this: A few seconds after you connect to someone in the swarm the Sandvine application sends a peer reset message (RST flag) and the upload immediately stops. Most vulnerable are users in a relatively small swarm where you only have a couple of peers you can upload the file to. Only seeding seems to be prevented, most users are able to upload to others while the download is still going, but once the download is finished, the upload speed drops to 0. Some users also report a significant drop in their download speeds, but this seems to be less widespread. Worse on private trackers, likely that this is because of the smaller swarm size.
This is such bullshit. Just after I switched from AT&T DSL to Comcast cable, (fucking Time Warner had to go and get bought out) they pull this shit. Even worse, I just cleared my entire hard drive to free up space for my custom chopped and screwed mixtapes. I gave up LimeWire long ago, and have no plans to go back, so I guess I'll have to work on some encryptions or, as the article suggest, set up a more secure VPN or SSH connection. More on this if I can connect later.