Torrent and Comcast

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

Although BitTorrent protocol encryption seems to work against most forms of traffic shaping, it doesn’t help in this specific case. Setting up a secure connection through VPN or over SSH seems to be the only solution. More info about how to setup BitTorrent over SSH can be found here.

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jivetrky said:

Take a look in your event viewer and see if you are getting events with the number 4226.

I never had this issue until the last month or two. But when it started, I would startup utorrent and my internet connection would DIE. The issue is that windows was limiting the TCP connections. I'm not sure if it was a recent patch that caused it for me or what, because as I said, before I didn't have this issue.

But to fix it, I found this program that patches the TCPIP.sys


download this program and change the limit to something like 100 or 150 and it should be much better for you (assuming this is the problem; as I said, check your event viewer, it'll tell you)


For the record, I'm not on Comcast. And when I was (previous to Oct 2008), I didn't have issues. In utorrent, make sure you set your protocol encryption (Options > Preferences > Bittorrent > Outgoing Protocol Encryption)

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