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Comcast Intercepts and Redirects Port 53 Traffic

An anonymous reader writes "An interesting (and profane) writeup of one frustrated user's discovery that Comcast is actually intercepting DNS requests bound for non-Comcast DNS servers and redirecting them to their own servers. I had obviously heard of the DNS hijacking for nonexistent domains, but I had no idea they'd actually prevent people from directly contacting their own DNS servers." If true, this is a pretty serious escalation in the Net Neutrality wars. Someone using Comcast, please replicate the simple experiment spelled out in the article and confirm or deny the truth of it. Also, it would be useful if someone using Comcast ran the ICSI Netalyzr and posted the resulting permalink in the comments.

10 of 527 comments (clear)

  1. Re:Fuck `Em All by CorporateSuit · · Score: 3, Insightful

    From your post, I don't think you're aware that Time Warner is actually one of the presiding members of the RIAA (and the MPAA).

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  2. Is this happening for ANYONE? by Itninja · · Score: 5, Insightful

    Was the original poster a shill for some other ISP or what? An anonymous user submits a story decrying a great technical wrong by Comcast, that no one appears to be able to reproduce. So a little fact check action might in order here. Up next, "toyotasuxors@ford.com says: Toyota tracking all US drivers with a device hidden in the glove box!

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  3. Re:Not happening to me by mea37 · · Score: 5, Insightful

    Just to be clear about the parameters of this test... I assume the PC from which you sent the request isn't on the same local network as the DNS server? (Since, you know, the ISP routers would never even see the traffic if it were?)

  4. Re:So let me see if I have this straight... by Alzheimers · · Score: 4, Insightful

    Welcome to the new Media Democracy.

  5. Re:Not happening to me by The+Moof · · Score: 4, Insightful

    Isn't that the point of this outrage?

    More like intercepting traffic that isn't destined for Comcast as if it were. You're not attempting to contact Comcast in any way, but that's where the traffic is ending up.

    Let's say Comcast, for some reason, suddenly decides that your site should no longer be reachable (by name), they could start intercepting DNS requests for your site and returning domain not found. Or worse, redirecting you to a site they find more "suitable."

  6. "Official Response" by rednip · · Score: 4, Insightful

    Wow it's nice to know that Comcast has both a twitter account and a brand new Slashdot account. Oh, it's most likely that you're an employee (maybe tech support), I'd watch what you call an 'Official Response' as many corporations have very strict rules about talking to the press, or making any binding claims to a general audience. Are you authorized for such communication? If so, I'd suggest a listing on the main corporate 'contacts' page, so that it'd be easy to verify it as 'official'. Also, the DNS team (or even the guy on duty) might not be complicit in the skulduggery, so your assessment might not be correct.

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    The force that blew the Big Bang continues to accelerate.
  7. Re:Not surprised by Kadin2048 · · Score: 4, Insightful

    The only way I can imagine they'd profit from this is by blocking access to alternative DNS servers like OpenDNS, or even just putting in well-known public DNS servers like 4.2.2.2, so that they can intercept unknown requests and return ad-laden pages instead. Basically typosquatting.

    Various ISPs have gone down this road before. (Rogers Cable has tried, and so has Road Runner.) Unfortunately -- for the shady ISPs, anyway -- it's easy for annoyed users to get around these schemes; they can just configure their computer or NATing router to use a different DNS server besides the one supplied by the ISP via DHCP.

    By transparently redirecting all DNS requests to their own servers, Comcast would eliminate this method of circumventing their advertising. They could also block sites at the DNS level much more easily than before.

    A lot of censorship schemes (ab)use DNS in order to return a bogus result to a query; these schemes aren't very good, though, because any user with two brain cells to rub together and the tiniest bit of motivation can change their DNS configuration to use clean servers instead. By doing transparent redirection, you prevent this.

    Those strike me as the two obvious reasons. The profit-motivated one (squatting on failed DNS queries) is annoying and causes many non-web applications to fail or behave improperly, but it's not nearly as bad as the censorship-motivated one is. However, the same technique that makes failed-lookup ads harder to avoid could easily be used as part of a censorship scheme if demanded by the government. It's important that even casual Internet users (who may not really care about returning a "page not found" web page instead of the normal browser message) understand why letting their ISP monkey with DNS lookups is a Really Bad Idea.

    In both cases you can get around the hijacking by using a VPN and forcing DNS queries though it, but that's significantly harder than changing from automatically-assigned DNS servers to well-known ones like OpenDNS's or Verisign's.

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  8. Re:Not happening to me by Zetta+Matrix · · Score: 5, Insightful

    Isn't that the point of this outrage? Getting typojacked when you try to go to a genuinely invalid URL?

    Actually, no. We've been outraged about that before. It's one thing if I use someone's server and it typojacks me due to a wildcard entry in the name tables. The alleged behavior we're discussing actually prevents* the user from using another nameserver outside of that ISP in order to sidestep the problem.
    * (well, makes more difficult, requiring tunneling or something like that)

    For quite awhile I've had the feeling that DNS will eventually be brokered through P2P/DHTs/etc with digitally signed payloads, and this type of behavior only makes that idea more appropriate.

  9. Re:Not happening to me by cprincipe · · Score: 3, Insightful

    This is retarded.

    I point my router's DNS to OpenDNS.org and everything works great. If I type a BS domain I get the OpenDNS search page.

    One idiot's Wordpress blog is enough to make it to the front page? I mean, I think Comcast is the devil incarnate, but there are plenty of legitimate reasons to hate them without making up BS stories.

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  10. Re:Official Response by Linux_ho · · Score: 4, Insightful

    Even assuming you're a real Comcast representative, why should we believe anything any Comcast rep says, after witnessing the series of lies, stonewalling, and misdirection Comcast produced after being accused of interfering with BitTorrent traffic, and then again after being caught red-handed interfering with BitTorrent traffic?

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