Does any packet transfer( fin,rst ) happen after tcp detects connection timeout occured ?? - TCP-IP

This is a discussion on Does any packet transfer( fin,rst ) happen after tcp detects connection timeout occured ?? - TCP-IP ; Hi All, I want to know if, for connection which TCP detects as timeout occured , does it try to send FIN packets/RST packets after detecting so. Or it simply discards everything about that conn and conn no more exists ...

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Thread: Does any packet transfer( fin,rst ) happen after tcp detects connection timeout occured ??

  1. Does any packet transfer( fin,rst ) happen after tcp detects connection timeout occured ??

    Hi All,
    I want to know if, for connection which TCP detects as timeout
    occured , does it try to send FIN packets/RST packets after detecting
    so. Or it simply discards everything about that conn and conn no more
    exists from its point of view.If it sends FIN packets or so, does it
    again wait for complete timeout to occur before giving up even though
    it knows the connection timeout has already occured for this
    connection ??


    --Rohit


  2. Re: Does any packet transfer( fin,rst ) happen after tcp detects connection timeout occured ??


    Rohit writes:
    > I want to know if, for connection which TCP detects as timeout
    > occured , does it try to send FIN packets/RST packets after detecting
    > so. Or it simply discards everything about that conn and conn no more
    > exists from its point of view.If it sends FIN packets or so, does it
    > again wait for complete timeout to occur before giving up even though
    > it knows the connection timeout has already occured for this
    > connection ??
    >


    Any reasonable TCP stack sends RST segment after final
    re-transmission timeout. Socket is closed after that. There is
    no point to expect that FIN handshake would work after
    multiple unsuccesful retransmissions of previous segment.

    -ilkka

  3. Re: Does any packet transfer( fin,rst ) happen after tcp detects connection timeout occured ??

    Ilkka Oksanen wrote:
    > Any reasonable TCP stack sends RST segment after final
    > re-transmission timeout. Socket is closed after that. There
    > is no point to expect that FIN handshake would work after
    > multiple unsuccesful retransmissions of previous segment.


    Well, the RST isn't necessarily any more likely to get there than the
    FIN, but if it does, it does communicate the "right" message, which is
    that the connection is toast.

    Especially if the RST is from a stack which actually "extends" the RST
    segment with some ASCII for the abort reason Of course one only
    sees that with a packet sniffer...

    rick jones
    --
    Process shall set you free from the need for rational thought.
    these opinions are mine, all mine; HP might not want them anyway...
    feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...

  4. Re: Does any packet transfer( fin,rst ) happen after tcp detects connection timeout occured ??

    In article ,
    Rick Jones wrote:

    > Ilkka Oksanen wrote:
    > > Any reasonable TCP stack sends RST segment after final
    > > re-transmission timeout. Socket is closed after that. There
    > > is no point to expect that FIN handshake would work after
    > > multiple unsuccesful retransmissions of previous segment.

    >
    > Well, the RST isn't necessarily any more likely to get there than the
    > FIN, but if it does, it does communicate the "right" message, which is
    > that the connection is toast.


    The problem could be in the reverse direction. So the FIN or RST would
    reach the other end, and the failure could be with the ACKs. Since RST
    doesn't require an ACK, it seems like the correct way to let the other
    end know that the connection is failing. If the other end hasn't been
    trying to send any application data, it would never realize it (because
    it's not sending anything that requires ACKs).

    --
    Barry Margolin, barmar@alum.mit.edu
    Arlington, MA
    *** PLEASE post questions in newsgroups, not directly to me ***
    *** PLEASE don't copy me on replies, I'll read them in the group ***

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