Re: [tcpm] TCP zero window timeout?
Joe Touch <touch@ISI.EDU> Sat, 26 August 2006 02:49 UTC
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Date: Fri, 25 Aug 2006 19:48:08 -0700
From: Joe Touch <touch@ISI.EDU>
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To: Mahesh Jethanandani <mahesh@cisco.com>
Subject: Re: [tcpm] TCP zero window timeout?
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Cc: "Mahdavi, Jamshid" <jamshid.mahdavi@bluecoat.com>, tcpm@ietf.org, "Anantha Ramaiah (ananth)" <ananth@cisco.com>, Fernando Gont <fernando@gont.com.ar>
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Wouldn't this just result in the DOS attacker ACKing one byte at a time to prolong the connection needlessly? I.e., what's the point of putting this behavior inside TCP, vs. having the server give up on a connection after what it considers a reasonable time? Joe Mahesh Jethanandani wrote: > Jamshid, > > Looking at draft-ietf-tcpm-tcp-uto it appears that the draft is > specifically looking at the question of disconnection in the network. It > also applies to retransmission timer. > > The situation I was referring to is a little different and applies to > persist timer. In our situation the client stops reading data. These > clients are machines out in the Internet and as such the server has no > control over their behavior. So while there is unacknowledged data, it > is not that the client is not acking any data. It is responding to the > probe but that it continuously advertises a window of zero. There is > currently to my knowledge no timeout for this state for the server. This > can manifest itself as a DOS situation if there are several such > connections where the server is forced to hold data. > > We are suggesting a solution that allows the server to get out of this > situation by applying a upper bound on the duration of the persist > state. Note, it is not the default behavior for TCP. The default > behavior is still the same. The user/administrator has to explicitly > turn it on for the server to close the connection and free the resources > in case it is believed that it is under attack. > > Fernando Gont wrote: >> At 13:24 21/07/2006, Mahdavi, Jamshid wrote: >> >>> What is the status of draft-eggert-tcpm-tcp-abort-timeout-option-01? It >>> may be of some use in situations like this. I've recently seen another >>> scenario where this would be useful, so I'd be interested in seeing that >>> draft reposted... >> >> It was merged with draft-gont-tcpm-tcp-auto-option into >> draft-ietf-tcpm-tcp-uto. >> >> The latest revision is draft-ietf-tcpm-tcp-uto-03.txt, available at >> the usual places (e.g., >> http://www.ietf.org/internet-drafts/draft-ietf-tcpm-tcp-uto-03.txt). >> >> Feedback is more than welcome. ;-) >> >> Kindest regards, >> >> -- >> Fernando Gont >> e-mail: fernando@gont.com.ar || fgont@acm.org >> PGP Fingerprint: 7809 84F5 322E 45C7 F1C9 3945 96EE A9EF D076 FFF1 >> >> >> >> >> >> >> _______________________________________________ >> tcpm mailing list >> tcpm@ietf.org >> https://www1.ietf.org/mailman/listinfo/tcpm > _______________________________________________ > tcpm mailing list > tcpm@ietf.org > https://www1.ietf.org/mailman/listinfo/tcpm
_______________________________________________ tcpm mailing list tcpm@ietf.org https://www1.ietf.org/mailman/listinfo/tcpm
- [tcpm] TCP zero window timeout? Mahesh Jethanandani
- RE: [tcpm] TCP zero window timeout? Mahdavi, Jamshid
- RE: [tcpm] TCP zero window timeout? Fernando Gont
- Re: [tcpm] TCP zero window timeout? Mahesh Jethanandani
- Re: [tcpm] TCP zero window timeout? Joe Touch
- Re: [tcpm] TCP zero window timeout? Fernando Gont
- Re: [tcpm] TCP zero window timeout? MURALI BASHYAM
- RE: [tcpm] TCP zero window timeout? Anantha Ramaiah (ananth)
- Re: [tcpm] TCP zero window timeout? Joe Touch
- Re: [tcpm] TCP zero window timeout? Kuthonuzo Luruo (STSD)
- Re: [tcpm] TCP zero window timeout? Ted Faber
- Re: [tcpm] TCP zero window timeout? Fernando Gont
- Re: [tcpm] TCP zero window timeout? MURALI BASHYAM
- Re: [tcpm] TCP zero window timeout? MURALI BASHYAM
- Re: [tcpm] TCP zero window timeout? Mahesh Jethanandani
- RE: [tcpm] TCP zero window timeout? Caitlin Bestler
- RE: [tcpm] TCP zero window timeout? MURALI BASHYAM
- Re: [tcpm] TCP zero window timeout? Fernando Gont
- Re: [tcpm] TCP zero window timeout? Ted Faber
- Re: [tcpm] TCP zero window timeout? MURALI BASHYAM
- RE: [tcpm] TCP zero window timeout? Caitlin Bestler
- Re: [tcpm] TCP zero window timeout? John Heffner
- RE: [tcpm] TCP zero window timeout? MURALI BASHYAM
- RE: [tcpm] TCP zero window timeout? Caitlin Bestler
- Re: [tcpm] TCP zero window timeout? Mahesh Jethanandani
- Re: [tcpm] TCP zero window timeout? Joe Touch
- Re: [tcpm] TCP zero window timeout? Ted Faber
- Re: [tcpm] TCP zero window timeout? Joe Touch
- Re: [tcpm] TCP zero window timeout? Ted Faber
- Re: [tcpm] TCP zero window timeout? Joe Touch
- Re: [tcpm] TCP zero window timeout? Ted Faber
- Re: [tcpm] TCP zero window timeout? Ted Faber