Re: [tcpm] SYN in SYN_RCVD state
"Vishal Study" <vishal.study@gmail.com> Mon, 22 October 2007 19:39 UTC
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Date: Mon, 22 Oct 2007 12:37:23 -0700
From: Vishal Study <vishal.study@gmail.com>
To: Ted Faber <faber@isi.edu>
Subject: Re: [tcpm] SYN in SYN_RCVD state
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Hi Ted: The server would retransmit SYN+ACK when server times out in SYN-RECEIVED state. I agree and have seen this. But, when the server hasn't timed out in SYN-RECEIVED state and it receives retransmitted SYN from client (due to client's timeout), what is the expected behavior on server side? Is server supposed to send SYN+ACK? Thanks! On 10/22/07, Ted Faber <faber@isi.edu> wrote: > On Sun, Oct 21, 2007 at 04:25:25AM -0700, Vishal Study wrote: > > > Vishal Study ha scritto: > > > > Consider the following scenario: > > > > > > > > 1. TCP client sends SYN to server; server goes to SYN_SENT state > > > > > > > > 2. server responds with SYN+ACK; server goes to SYN_RCVD state > > > > but SYN+ACK sent to client is lost somewhere in the network. > > > > > > > > 3. client re-sends SYN on its timeout (couple of seconds later) to server > > > > > > > > What should be the server behavior? Should it retransmit SYN+ACK or > > > > should it send a RST? > > > > > > But RFC 793, pg 71 seem to say that the server should send out a RST > > if SYN is rx in SYN-RCVD state (assuming SYN seq number is within the > > window, which is true in the example I had mentioned). > > > > Any thoughts on this? > > I think that because RCV.NEXT was set to SEG.SEQ+1 when the "server" > entered SYN-RECEIVED state (as documented on page 66 of 793) the resent > SYN is outside the window and will be acked. The "server's" SYN+ACK > will be resent if it times out. > > -- > Ted Faber > http://www.isi.edu/~faber PGP: http://www.isi.edu/~faber/pubkeys.asc > Unexpected attachment on this mail? See http://www.isi.edu/~faber/FAQ.html#SIG > > _______________________________________________ tcpm mailing list tcpm@ietf.org https://www1.ietf.org/mailman/listinfo/tcpm
- [tcpm] SYN in SYN_RCVD state Vishal Study
- Re: [tcpm] SYN in SYN_RCVD state Vishal Study
- RE: [tcpm] SYN in SYN_RCVD state Agarwal, Anil
- Re: [tcpm] SYN in SYN_RCVD state Ted Faber
- Re: [tcpm] SYN in SYN_RCVD state Vishal Study
- Re: [tcpm] SYN in SYN_RCVD state Ted Faber
- Re: [tcpm] SYN in SYN_RCVD state Joe Touch