Re: [tcpm] TCP zero window timeout?
Fernando Gont <fernando@gont.com.ar> Sat, 26 August 2006 11:25 UTC
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Date: Sat, 26 Aug 2006 07:13:56 -0300
To: Mahesh Jethanandani <mahesh@cisco.com>, "Mahdavi, Jamshid" <jamshid.mahdavi@bluecoat.com>
From: Fernando Gont <fernando@gont.com.ar>
Subject: Re: [tcpm] TCP zero window timeout?
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Cc: tcpm@ietf.org, "Anantha Ramaiah (ananth)" <ananth@cisco.com>
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At 21:00 25/08/2006, Mahesh Jethanandani wrote: >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. I'd argue that this should be handled by an application-level timer. The problem with the scenario you point out is that there will always be one more way to do the same thing. If we're talking about connections wasting resources, there are many protocols (POP3, SMTP) in which after the initial greeting by the server, the client is supposed to go ahead. In all those cases, the client could just sit there. And only an application-layer timeout would help you. I'm not sure how many servers implement this type of application-layer timer. But there are some (Apache) that I have checked, and do. Nevertheless, I'm interested in the behaviour you described. Is it supposed to be malicious activity? 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] 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