Comcast Wrongfully Denies Interfering with BitTorrent
Written by Ernesto on August 22, 2007Last week we reported that Comcast is making it impossible for its customers to seed files on BitTorrent. Not surprisingly, Comcast’s PR department does all it can to deny there allegations, but we - and with us some of the leading BitTorrent developers - know better.
So who’s right here? The hundreds of people that seem to have the same seeding problem, or the Comcast spokesman Charlie Douglas, who denies that Comcast is monkeying with BitTorrent bandwidth. Apparently Comcast want people to believe the latter, even though all evidence points in the other direction. Decide for yourself.
Moxie, a Comcast customer who replied to a post on Silicon Alley, points out that when you log your network activity with an application like Wireshark, you’ll notice that Comcast servers start sending reset messages as soon as a download is finished, exactly as we described it.
With Wireshark in the background run your BitTorrent application. Wait until completed and watch Wireshark, notice when it finishes seeding Comcast servers send out a reset command every second to your computer noted by the highlighted red line in Wireshark. It is 8:30 pm Monday pst and Comcast is still resting my BitTorrent connections. Maybe the PR guy didn’t get the email from the VP of Networking.
It might be that not every Comcast customer is equally affected, but a significant percentage is. Not only the 10+ users we talked to before we first reported this issue, but also hundreds of additional commenters here on TorrentFreak, and elsewhere. Some users even captured the throttling in progress on video (download), and anyone has to agree that this does look very suspicious.
More evidence comes from Robb Topolski, a networking and protocol expert with more than 25 years of experience, who first wrote about this issue on DSLReports. He told TorrentFreak: “We have had two Comcast techs confirm Sandvine in use, but neither confirmed or denied its connection with the RST interference. For me, seeding is possible. I can reach my upload speed limit, but there sure is a lot of interference. Since your article came out, I too have received many reports of seeding being impossible. I’m not sure if it’s regional, or what!”
For the networking savvy people among us, here’s an example of real RST interference on an unencrypted BitTorrent connection. In this case, it happens right after the bitfields are exchanged
Nevertheless Comcast spokesman Charlie Douglas said in a response to Light Reading: “We’re not blocking access to any application, and we don’t throttle any traffic”. He might be right here semantically speaking, they are not throttling anything, they just kill all outgoing connections when a clients starts to seed a file. But the fact is that Comcast is making it impossible for (at least some) customers to share files with non-Comcast users over BitTorrent.
Luckily there is a fix for this problem, and we know that at least two BitTorrent client developers are including this fix in their next update.
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130 Responses
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Instead of investing in anti-p2p appliances and software, which will work only a couple of weeks (as shown in this case), they should get their stuff together and invest in their infrastructure. ISPs in other countries can do it, why shouldn’t Comcast be able to.
Oh well, it’s Comcast.
Is there a way to block the reset message? I mean if you can block an incoming ping, you can just as easily block a reset message. Also, I always thought DoS was illegal. I can imagine that businesses using bittorent as apart of their network would be rather angry about this. They probably will not be using comcast very much longer.
Digg it!
http://digg.com/tech_news/Comcast_Wrongfully_Denies_Interfering_with_BitTorrent
“Luckily there is a fix for this problem, and we know that at least two BitTorrent client developers are including this fix in their next update.”
Which ones in particular?
[quote comment="150614"]
Which ones in particular?[/quote]
I know for sure that uTorrent is addressing the problem.
I have to say I’ve been seeding a completed torrent on and off for three days straight and have had no interference of any kind. As comcast customer I’ve been waiting for this, but I’m not seeing it now….
Hoping I’m right or we get around this…
[quote comment="150582"]Is there a way to block the reset message?[/quote]
Some people report that BitTorrent encryption works for them.
http://torrentfreak.com/how-to-encrypt-bittorrent-traffic/
Other options are BitTorrent over VPN or SSH.
I’m just hoping that if uTorrent fixes this, then the first version of the Mac uTorrent client has this feature as well. As a member of a popular pink bittorrent site where seeding is hard enough as it is, I’ve been getting hurt pretty bad lately. It used to take me 4-5 days to get to a 1.0 ratio on a torrent, it now takes me 2-3 weeks to get to a 0.1 ratio, and I’ve been experiencing this since about December of last year. Damn Comcast and their monopoly in my region. If I could get DSL, I’d have it already.
You can block the RST message.
The issue is how you identify the fake RST. Because you do need RST messages for proper operation of TCP and RSTs are all the same.
However… if you only plan to use BT, blocking the RST will do it.
[quote comment="150756"]You can block the RST message.
The issue is how you identify the fake RST. Because you do need RST messages for proper operation of TCP and RSTs are all the same.
However… if you only plan to use BT, blocking the RST will do it.[/quote]
please explain how to do that
It happened here in Boulder, CO. I called to cancel.
The first person I talked to at Comcast had no idea what I was talking about so I called again. The second person confirmed this and with that, I am moving to 7 Mbps DSL in hte next week.
Of course their not gonna admit to screwing with your connection. The second they admit to that, they start loosing business, and they open up the door for the competition, in this case fios, to start the poo slinging. No matter what morales a company may claim to have, if lying makes you more money, then truth simply becomes merely one mans perception of an assumed fact. Screw em, they dont do the contract thing, drop the service if you have it and go fiber if it’s available. Hell the upload speeds are around 2 megs, so at the very least, your ratios will get a whole lot better. - CJ
Where does uTorrent say they are making a fix for this? I can’t seem to find it and they said it was more of an OS level problem.
I am a Comcast customer and NONE of my Bitttorrent traffic has been affected.
[quote comment="150800"]I am a Comcast customer and NONE of my Bitttorrent traffic has been affected.[/quote]
Thats because you’re stupid.
I’ve found that activating the myriad connection obfuscation features in Azureus makes it possible for me to seed.
Originally, I left those options off for fear of creating unnecessary overhead and slower connections to peers, but slower is better than being straight-up denied. I’ve noticed I connect to fewer peers now for seeding, but still seem to be able to use all my upload speed.
i can confirm that Sandvine is all over that! they have their PTE’s and PPE’s across the COMCAST network and they do throttle all kinds of P2P connections. just goes to show that large corporations take our money, don’t upgrade their networks, and then have to pull stunts like this one.
I can confirm that Boston, MA area comcast is killing seeds. Still waiting for Comcasts craptastic monopoly to allow Verizon FIOS in my area. Bastards.
[quote comment="150800"]I am a Comcast customer and NONE of my Bitttorrent traffic has been affected.[/quote]
Comcast is a very large network, which has grown through mergers and acquisitions of smaller, separate networks. You might be in such an area.
That’s part of the problem with what Comcast is doing, here. They have not said how this works (or that it even exists), so when customers have a real problem involving P2P management, they have no way to get support.
Anonymous tech,
Yes, with a good firewall you can block RST (peer reset) messages.
Author,
Two alternatives, alternative one and alternative two. Alternative one is former, alternative two is the latter.
I think you meant to say that Comcast wants people to believe the former, that hundreds of people are having the same seeding problem.
“…I’m not sure if it’s regional, or what!”
It wouldn’t take much stretch of the imagination to consider that comcast deliberately choses random accounts at random times to throttle, to further add to the confusion we’re seeing here. This sounds like the most likely scenario given Robb Topolski’s experience.
Im on the west coast, using a Mac on Comcast, cannot seed, download speeds seem unusually slow. ..
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