Comcast Tries To Sterilize, Decapitate BitTorrent

Comcast is reportedly stabbing at the heart of the file transfer protocol BitTorrent by preventing users from seeding torrent files. Seeds are completed BitTorrent downloads shared with other users; without seeders, the BitTorrent protocol does not work, much the way a garden can’t grow without seeds. Comcast’s draconian throttling solution utilizes a program from Sandvine that affects all files distributed through BitTorrent, regardless of whether the shared file is an illegally downloaded movie, or a legal distribution of Linux. From TorrentFreak: 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.

According to Light Reading, Comcast has issued a carefully worded denial:

“We’re not blocking access to any application, and we don’t throttle any traffic,” says Charlie Douglas, a Comcast spokesman.

Douglas didn’t explicitly deny the use of deep packet inspection or traffic shaping products. “[Comcast] has a responsibility to manage our network to ensure our customers have the best service, and we use available technologies to do so.”

We’d be happy to live in a world where the absence of this unabashed corporate machismo made government regulation unnecessary, but Comcast would rather cry free market and gallivant over their users in search of more profit. Their own actions are the most convincing argument in favor of net neutrality.

Comcast Throttles BitTorrent Traffic, Seeding Impossible [TorrentFreak]
(Photo: CarbonNYC)


Edit Your Comment

  1. Benny Gesserit says:

    Here in Canada, Rogers (and a few of the Telco ISPs) have been using something called “Bandwidth Shaping” to, at least, reduce the use of Bittorrent. I’m not a tech so I can’t speak with confidence but it appears to ‘sense’ torrent traffic (both seeding and leaching) and throttles the speed back.

    You want that 8Gig disk image of “Naughty Nurses 2006”? Well at 2-3K/second we’ll see you in a month or two, ya hoser.

  2. timmus says:

    Umm… seeing as Comcast is one of those ISP’s that blocks outbound Port 25 (SMTP), then a statement like “We’re not blocking access to any application” is false, hence nothing else the spokesman says can be trusted.

  3. doctor_cos wants you to remain calm says:

    I fail to see the difference it makes, as we are quickly on our way to becoming a third world country in terms of ‘broadband’ speed here in the US. Our average broadband speed sucks compared to several other countries, thanks to such wonderful folks as Comcast who can hide behind the ‘infrastructure won’t support it’ and ‘customers don’t really want it’ excuses.

  4. j-o-h-n says:

    This ‘Sandvine application’ appears to me to be using a method protected by U.S. patent #6,044,402

  5. jtlight says:

    All this will do is force Torrent users to encrypt their torrents (which any good program will do). Torrents and P2P aren’t going away, and any time sometime tries to stop it, all it does is spur more people to use it.

  6. sleze69 says:

    @jtlight: Actually, it appears that encryption doesn’t appear to be effective against this type of disruption. But I have faith in the BT app developers to get around it soon enough.

  7. Hanke says:

    Hmm…wonder how this affects programs such as ‘World of Warcraft’ that use a torrent-like system to distribute their patches.

  8. dukrous says:

    This has nothing to do with net neutrality. It’s about the last mile of access. Comcast knows you can’t go anywhere else for cable internet, so they can do as they please. If there was true competition in the ISP market, then net neutrality will continue to be the non-issue it has always been.

    Instead, you could create specialized ISPs. Imagine an ISP who shapes traffic for better WOW or EQ access, or another who gives you the fastest web connections it can. This is what competition can do. The key is less government regulation…never more.

  9. mrsultana can't get a password to work says:

    Out of curiosity, does this mean that as a Comcast customer, I can use bittorrent to download copyrighted material legally?
    Since the laws are written and the courts have ruled repeatedly that uploading or making available for upload any copyrighted material is illegal, Comcast just made sure that I can’t get successfully sued by the RIAA or MPAA. Yeah, it sucks being a leecher, but the defense just have to say that I was aware that nobody could infringe on the copyright because Comcast would throttle those attempts.
    So long as there is someone out there using bittorrent and not Comcast, everything should be cool.

  10. tedyc03 says:

    I think that someone trying to transfer a legal file with BitTorrent should sue Comcast for breach of contract. Comcast’s contract says that they provide communications service; the individual couldn’t communicate; thus the contract is breached.

    Comcast is really trying to protect their own interests here; movies and television shows are being downloaded via bittorrent and they are not making money in cable revenue. Sounds like a conflict of interest to me (something else that might give rise to a cause of action).

  11. Jean Naimard says:

    Countries with effective broadband have effective broadband precisely BECAUSE of government regulation.

    If only anglo-saxons would get their heads out of their arses and start looking elsewhere to see that the government can do useful things instead of instantly dismissing anything it does as bad, evil or corrupted.

  12. Cowboys_fan says:

    @jtlight: Just use utorrent.

  13. nweaver says:

    The onyl way the bittorrent developers can get around it is to make things DELIBERATELY inefficient:

    If you are seeding in the comcast space, you still fetch blocks from your peers so it doesn’t look like you are being leeched off of.

    Thus the countermeasure will cost Comcast MORE bandwidth!

  14. ExVee says:

    …I’m sorry, have you met the US government? In any case, I don’t see anybody being able to stop BitTorrent over the long term by doing anything short of shutting off home internet access entirely. And even then I have my doubts!

  15. Televiper says:

    Rogers in Canada has been doing something similar for quite awhile now. First they would simply throttle whatever port you were using to leach the torrent. Then they moved to this “packet shaping” technique. uTorrent and several other programs get around this through encryption. I don’t know if they are using the same technique at Comcast.

    I doubt they’re breaching contract. They probably have clauses about internet activity they deem disruptive to their network.

  16. TonyTriple says:

    What? You mean carve up traffic to give priority to certain forms of data has nothing to do with Net Neutrality? Bits are bits. It should not matter whether I am receiving packets from a porn site, a WOW server, or

    This has a lot to do with net neutrality and the ongoing battle over the classification of ISPs. Should an ISP be regulated, if so, should it fall under Title II (common carriers) regulation, or should the FCC remain hands off with regards to the internet?

  17. Televiper says:

    @ExVee: The trouble with the US government is the cynicism of government regulation which leads to favoring the industries they’re regulating. Look how good deregulating the electrical grid worked out.

  18. yg17 says:

    @dukrous: Fuck that. I want an ISP that just gives me the best service for my money and doesn’t speed up or slow down traffic based on what I’m doing. I want my internet connection to handle whatever I’m doing that day, whether it’s BitTorrent, web surfing or gaming.

  19. balthisar says:

    FYI, still able to seed here in SE Michigan.

  20. wolftrouble says:

    I can confirm that I haven’t been able to seed for weeks, in San Jose. I don’t use bittorrent all that often, so I just figured maybe I had a weird firewall setting or something, but I confirmed it on an unfirewalled connection with another system. Time to ring up a DSL provider or two and see what they can do.

  21. CoffeeAddict says:

    I am so thankful I am not a customer of Comcast. I do see alot of their customers so this will be helpful in pointing fingers to who is at fault. I go through a canadian ISP called Shaw Cable and although they don’t seem to be throttling just yet I can definately see it on the horizon. I hope the government is watching and plans to crack down on these corporate giants who believe that the almighty dollar is more important then their customers. They soon may find out that they have no customers.

  22. jamar0303 says:

    I live in *China* and the ADSL provider here doesn’t block torrents or anything (well, we all know exactly what they do block). Comcast won’t be my provider for sure when I get back to the States, even if it means I’m getting Verizon (and if they start traffic shaping… Hello Japan, and hello 100Mbps FTTH).

  23. Vitalis says:

    If you think the Government is going to be any help in this issue at all, you’re nuts. The problem is, the large corporations are all in bed with the Government. The free market would work, if it was truly free. Or maybe I’m just a crazy anglo-saxon who doesn’t like my Government dictating what I do, say or think…

  24. Scazza says:

    @Jim (The Canuck One): Hey Jim, Toronto Rogers user here and I don’t see any torrent raping here. I can usually get over 300kbs on most torrents and MUCH higher if its a bigger shared file.

  25. nctrnlboy says:

    would this effect the old p2p downloading? I dont use torrents.
    About 3 weeks ago my Frostwire p2p downloading client just absolutely went to shit & would only download at 2-10 kbs max. All of a sudden it happened, when it had been working great for over a year. I downloaded the latest frostwire & java updates, but it made no difference. I finally just gave up & went back to limewire & now I can download like I used to be able to with frostwire (anywhere from 50kbs-120kbs).
    And before anyone starts in with how better torrents are than the old p2ps like limewire,kazaa,frostwire etc.etc…. save your breath.
    On the matter of comcast using programs to stop torrents… How the hell can they do this? Torrents arent ALL illegal downloading! Downloading is what the internet is all about now. WHY would anyone get a high-speed internet connection if not to download large files via torrents? (streaming video aside)

  26. MudMt says:

    I’m a Comcast customer and a sometime distro and Subbed show seeder, and this has completely killed that. =( and no guys, you can’t just “Encrypt” and get rid of it. Much as it sucks, I’m screwed. Comcast may leave downloading possible, but I refuse to leech from the Swarm.

    Trouble is, the only other company out here is AOL(Shudder) and “clearwire” who are no great either. Fair well old BT friend, you were so kind to me.

  27. bontakun says:

    The work around for this issue:
    iptables -A INPUT -p tcp –dport btport –tcp-flags RST RST -j DROP

  28. bohemian says:

    I have to wonder if there is some form of VPN that could be used to get around this. If they are finding a way to break in to a VPN connection the ISP could get in a bunch of trouble. Lots of home office workers use VPN to get into programs and information at work. If someone at Comcast or another ISP were to break into a VPN connection that contained company information they could probably get in really big trouble.

    On a similar subject. Has anyone had issues connecting to just google properties. We have had the same problem with two ISPs. We can get just about any other website with a fast response. Try hitting ANY google owned website and it times out and you have to try about three times before you finally get through.

  29. lcaa9 says:

    I live in Canada, too, and Shaw also uses Bandwidth Shaping. However, Shaw seems to endorse file sharing:


  30. dgtldrmr says:

    @BONTAKUN: How do I put that line into UTorrent?

  31. @bontakun: That’s not bad of an idea… You tell me how to work that into retail router firmware (no possible way to load DD-WRT on a WRT54Gv8 at the moment) and you’ll have done us a great justice…

  32. randalotto says:

    There’s a good discussion of this issue over at slashdot.

    an anonmyous coward makes the argument that the “iptables…” solution is actually not that great an idea, as there are “legitimate reasons” you want the tcp flags to remain as they are. it’s all a bit over my head, but the thread has alot of good info.


  33. Pec says:

    I have been able to seed torrents for many years, on multiple operating systems through my standard 6meg comcast connection in southeast michigan.
    Average about 45-55kp/s up.
    If this ever becomes prevented comcast will be losing a customer of 15-years.

  34. dukrous says:

    @TonyTriple: There are positive effects to bandwidth shaping. Think of it like cable TV packages. You can find the ISP that gives you exactly the service you want at a price you are willing to pay. I don’t see that as a bad thing, I think it’s a great thing. If you want a general service ISP, go find one…want a specialized one, go find it. Increasing choice on the market by eliminating the default monopolies ISPs…how is that a bad thing?

    It will also reduce the threat any ISP can level against you. An ISP starts to act in a way you don’t like, switch services. Vote with your wallet…if enough agree, they go out of business or change their policy. In the end, businesses are there to make money, not fuck you any way they can…if they can make more money by being your friend, they’ll do so. Until then, nothing is stopping them from assraping their customers because there is no free market for them to compete in.

  35. theblackdog says:

    Thank God that in 2 weeks I am becoming a Verizon DSL user. No more Comcrap for me!

  36. kbarrett says:

    The iptables command only works if you are on a UNIX based system.

    Let’s say you are using ubuntu, and your bittorrent program listens on port XXXXX ( you can find out the real number for which port you are on in your btt settings, and substitute that for XXXXX ), then you would open up a terminal window, and enter this command:

    sudo iptables -A INPUT -p tcp –dport XXXXX –tcp-flags RST RST -j DROP

    The shell session will demand your password to implement the command after you hit enter.

    This will add an entry to your iptables firewall list … it will watch for incoming tcp packets on port XXXXX that contain the tcp flag RST, and then just drop them on the floor when they appear.

  37. Well… 3 days or so since this all began and those flags are flying high… Unfortunately, my router doesn’t support DD-WRT, HyperWRT or any other 3rd party firmware so I can’t drop in the iptables fix. Unless someone figures out how to do this in windows or on stock WRT54Gv8 and v6 firmware, I’m screwed, atleast until Verizon gets their firmware out here… In 2010…

  38. dgtldrmr says:

    @dukrous: Sure, that’s fine but what do you do when Comcast is the ONLY high speed ISP in town?

  39. Benny Gesserit says:

    @Scazza: Bandwidth shaping appears to be useless if you use a client that is capable of encrypted traffic. If you’re using a new-ish client (uTorrent or even BitTorrent), it’s likely they can’t even see you. Enjoy!

  40. royal72 says:

    this is a waste of time and energy by comcast and anyone else trying to stop file sharing on any level for several reasons:

    (a) bittorrent apps will probably be adapted to compensate.

    (b) a new file sharing format is always on the horizon.

    (c) as long as your corporate greed continues, pirates will have no moral reservations to steal “your” intellectual properties.

  41. Havok154 says:

    I love how so many corporations are screaming about the evils of BT apps, but they don’t take into the account of all the legal programs using P2P. Many companies use BT programs to distribute updates, patches, and their own programs. I’d like to see Blizzard or Linux devs start fighting back since they all use BT for legitimate reasons and all this crap can hurt their distribution model.

  42. siberian1967 says:

    The method I use to bypass Comcasts throttling is to set up an SSH tunnel to my server and configure UTorrent to use localhost as the SOCKS4 proxy.

    This allows the packets in question to route outside of comcast.

    Since then my seeds work great and things are back to normal since Comcast just views my connection as a standard ssh session.

    Of course, this only works if you have an SSH shell you can log into.

  43. suckonthat says:

    I am so glad I found this article. I couldn’t figure out why I would try downloading popular torrents and have 80+ peers, yet no seeds.

    I can confirm that there are work-arounds: VPN and utorrent. I believe azureus will also work.

    I plan on calling comcast tomorrow and bitching (they also decided to raise my DVR price despite having told me that my price would not go up when I initially agreed to it).

  44. bstewart23 says:

    Before I used encrypted uTorrent, Rogers (Toronto) had me sitting at 2-3 kbps. I called and was told by one rep — denied by another a day later — that they DO shape their traffic, and it IS allowed in their (inscrutable) contract with the customer. I gave detailed examples of how traffic shaping invalidates much of their advertising — not to mention grandfathering of previous service — and, coincidentally (?), within 10 minutes of hanging up, my speeds were up to 300 kbps.

    I have no explanation for this series of events and was disinclined to open a Pandora’s box which might reduce my speeds again.

  45. Stan LS says:


    “Our average broadband speed sucks compared to several other countries,”

    Dude, we are WAY bigger (geographically) then the other countries on that chart. Japan is the size of Montana!

  46. bionnaki says:


    What if your computer is behind a router? will the iptables command still work?