Problem with TCP Connection Close - Networking

This is a discussion on Problem with TCP Connection Close - Networking ; I am currently developing a tool using Python 2.4.2 which will be used as a sink to pump TCP messages. Something is going wrong while closing the connection. This i confirmed by looking at the ethereal logs, which show proper ...

+ Reply to Thread
Results 1 to 3 of 3

Thread: Problem with TCP Connection Close

  1. Problem with TCP Connection Close

    I am currently developing a tool using Python 2.4.2 which will be used
    as a sink to pump TCP messages. Something is going wrong while closing
    the connection.
    This i confirmed by looking at the ethereal logs, which show proper 3
    way FIN ACK Handshake. But the netstat reports TIME_WAIT state for the
    TCP connection, which is hindering the messages to be pumped later. I
    would like to know the probable cause for the problem.


  2. Re: Problem with TCP Connection Close

    -----BEGIN PGP SIGNED MESSAGE-----
    Hash: SHA1

    Madhur wrote:
    > I am currently developing a tool using Python 2.4.2 which will be used
    > as a sink to pump TCP messages. Something is going wrong while closing
    > the connection.
    > This i confirmed by looking at the ethereal logs, which show proper 3
    > way FIN ACK Handshake. But the netstat reports TIME_WAIT state for the
    > TCP connection, which is hindering the messages to be pumped later. I
    > would like to know the probable cause for the problem.


    What problem? According to the RFCs (RFC793, aka STD7), TIME-WAIT is the
    standard state that the closing end of a TCP connection should go to, once the
    closing handshake is complete.

    The RFC says:

    TIME-WAIT - represents waiting for enough time to pass to be sure
    the remote TCP received the acknowledgment of its connection
    termination request.

    Your connection is going into TIME-WAIT, just as it should. It will wait for a
    2MSL interval, just to make sure that the final ACK has made it to the other
    end, completing the close.

    /If/ you have need to reuse the TCP port in another connection, you should
    establish the *initial* connection with the SO_REUSEADDR socket option. In
    this way, sockets will not prevent you from reusing the port while the
    original user is in TIME-WAIT state.

    HTH
    - --
    Lew Pitcher

    Master Codewright & JOAT-in-training | Registered Linux User #112576
    http://pitcher.digitalfreehold.ca/ | GPG public key available by request
    - ---------- Slackware - Because I know what I'm doing. ------


    -----BEGIN PGP SIGNATURE-----
    Version: GnuPG v1.4.7 (GNU/Linux)
    Comment: Armoured with GnuPG

    iD8DBQFGPR2DagVFX4UWr64RAvvTAJ9ama8VDSgEYrmxFxZFNm ZjeiRuxACfe4sF
    1bCh6w5VwK3FPJ6dwqg94LI=
    =45DB
    -----END PGP SIGNATURE-----

  3. Re: Problem with TCP Connection Close

    On May 5, 6:23 am, Madhur wrote:
    > I am currently developing a tool using Python 2.4.2 which will be used
    > as a sink to pump TCP messages. Something is going wrong while closing
    > the connection.
    > This i confirmed by looking at the ethereal logs, which show proper 3
    > way FIN ACK Handshake. But the netstat reports TIME_WAIT state for the
    > TCP connection, which is hindering the messages to be pumped later. I
    > would like to know the probable cause for the problem.


    As long as the connection stays in TIME_WAIT for <= 2 MSL ( max.
    segment life time)..it is considered normal behavior..

    Kalyan


+ Reply to Thread