Comcast is using an application from the broadband management company Sandvine to throttle BitTorrent traffic. It breaks every (seed) connection with new peers after a few seconds if it’s not a Comcast user inside your community boundary. According to some Comcast technicians, who were brave enough to tell the truth, these Sandvine boxes are installed at the cable modem termination system. As a result, it is virtually impossible to seed a file, especially in small swarms without any neighboring Comcast users.
The good news is that there are several ways to fight back and get BitTorrent up and running again. Robb Topolski, a networking and protocol expert summed up some of the workarounds that reportedly solve the throttling issues.
What is working
1. Quite a few Comcast users report that forcing protocol header encryption completely eliminates the problems. This is the easiest solution since most BitTorrent clients support encryption. Please note that simply enabling encryption is not enough, it has to be forced. More details on how to do this can be found over here.
2. Another successfully workaround is to run BitTorrent over encrypted tunnels such as SSH or VPN. BitTorrent over SSH works, but it will cripple the servers of the SSH providers if you plan to use it permanently. A VPN service such as Relakks or VPNTunnel is a better option, and it is worth a few bucks.
3. Comcast prevents seeding, if you’re on a private tracker, and want to share as much as possible, an easy solution is to lower your download rate. When downloading, make sure that you have met your uploading goal by the time that the download completes. The easiest way to accomplish this is to set a download rate slower than the uploading rate. This of course is not an optimal solution because your download will never be faster than you upload speed.
4. One of the best options, if possible, is to switch to another ISP.
What is not working
1. Some people suggested that setting your firewall to drop RST packets could be effective, however, this is not the case. The RST-messages Comcast sends go in both directions, ignoring the RST on only one side creates a useless half-open connection.
2. According to most reports, enabling the Lazy Bitfield option in your BitTorrent client doesn’t solve the problem either
3. Reporting the issue to Technical Support. No explanation needed here.
4. Grab a hammer, visit the Comcast office, smash a keyboard and knock over a monitor. This might sound like a great alternative but apparently it only results in jail time.
I would advise affected Comcast subscribers to play around with these alternatives, some solutions that work for one person, might not work for another. Do you have another solution that is not reported here? Let us know in the comments!