NOQUEUE: Null connection from...

From: Bill Sadvary (sadvary_at_dickinson.edu)
Date: 05/02/03

  • Next message: Chris Los: "SUMMARY: Troubleshooting NTP time synchronization" 
    Date: Fri, 02 May 2003 13:41:58 -0400 (EDT)
To: Tru64-UNIX-Managers <tru64-unix-managers@ornl.gov>

    We're having problems receiving mail from just a handful of sites on the
    Internet. It's a really strange problem and one that maybe you can lend
    some assistance.

    I'll use "XXX.COM" as the remote site name in my examples with a
    bogus 123.123.123.123 as the IP address.

    I'm seeing this exact same problem and two different Tru64 v4.0g (fully
    patched, including all security patches) Alphaservers running Sendmail
    v8.8.8.

    Ok, Here goes...

    I can send mail to XXX.COM with no problem. But, when they send a message
    to us, it times out and goes undelivered.

    Here's the mail.log errors on our end..

    May 2 07:59:18 alpha sendmail[31795]: NOQUEUE: Null connection from
    XXX.COM [123.123.123.123]

    May 2 07:59:35 alpha sendmail[5014]: NOQUEUE: timeout waiting for input
    from XXX.COM [123.123.123.123]

    Upon talking with the XXX.COM NetMgr, he is seeing the TCP/IP 3-way
    handshake and then nothing else happens. He can telnet to port 25 of our
    mail server but gets no response when he issues the "helo" command. Very
    strange.

    He can ftp from XXX.COM to our mail server without a problem. We would
    have tried a regular, interactive telnet session but his firewall doesn't
    permit it.

    I did a test from my workstation by telneting to our mail server's port 25
    and then I just let the connection die on it's own and the mail.log showed
    the exact same error message.

    We're not blocking any XXX.COM mail via sendmail or the firewall.

    Any ideas why the connection gets established and then just dies? It
    doesn't appear to be a network problem since I cam email them and they can
    connect via ftp without a problem. It doesn't seem to be a DNS problem
    since the mail server is able to do the lookups for their site. It's seems
    like a sendmail issue on our end..

    Thanks,
    -Bill

  • Next message: Chris Los: "SUMMARY: Troubleshooting NTP time synchronization"