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rsp: 421 Command timeout

Discussion in 'SmarterMail' started by lmst, Mar 28, 2007.

  1. lmst

    lmst New Member

    I found out we had a lot of timeouts in the SMTP log.
    When I looked closer I found this pattern for many of them:

    13:31:45 [83.xxx.xxx.xxx][62943098] rsp: 220
    13:31:45 [83.xxx.xxx.xxx][62943098] connected at 2007-03-28 13:31:45
    13:31:45 [83.xxx.xxx.xxx][62943098] cmd: EHLO
    13:31:45 [83.xxx.xxx.xxx][62943098] rsp: 250- Hello [83.xxx.xxx.xxx] 250-SIZE 31457280 250-AUTH LOGIN CRAM-MD5 250 OK
    13:31:45 [83.xxx.xxx.xxx][62943098] cmd: MAIL From:<001617000244621@redcatbounce.domain1.com> SIZE=6699
    13:31:45 [83.xxx.xxx.xxx][62943098] rsp: 250 OK <001617000244621@redcatbounce.domain1.com> Sender ok
    13:31:45 [83.xxx.xxx.xxx][62943098] cmd: RCPT To:<xxxx@domain2.com>
    13:31:45 [83.xxx.xxx.xxx][62943098] rsp: 452 <xxxx@domain2.com> Mailbox size limit exceeded
    13:31:45 [83.xxx.xxx.xxx][62943098] cmd: RSET
    13:31:45 [83.xxx.xxx.xxx][62943098] rsp: 250 OK
    13:33:48 [83.xxx.xxx.xxx][62943098] rsp: 421 Command timeout, closing transmission channel
    13:33:48 [83.xxx.xxx.xxx][62943098] disconnected at 2007-03-28 13:33:48

    The same pattern is followed on many Greylistings as well.
    So there is a delay for about 2 minutes. Then timeout. Can somebody explain why?
    The sender and receiver are both legitimit.
    Lars
  2. ST-JLance

    ST-JLance New Member

    Looks like that mail server may just disconnect without sending the "QUIT" command, when it experiences a temporary error code.

    Also, the same is true for most spammers who encounter greylisting. When then get the 421, they just kill the connection rather than terminating it properly.
  3. lmst

    lmst New Member

    Could you also explain this:
    18:50:47 [213.7.112.75][57554553] rsp: 220 mail.domain.com
    18:50:47 [213.7.112.75][57554553] connected at 2007-03-28 18:50:47
    18:50:47 [213.7.112.75][57554553] Exception: System.Net.Sockets.SocketException: An existing connection was forcibly closed by the remote host
    18:52:51 [213.7.112.75][57554553] disconnected at 2007-03-28 18:52:51
  4. ST-JLance

    ST-JLance New Member

    That's just a standard socket error message meaning that the other end closed the socket without telling our side.
  5. kdovale

    kdovale New Member

    I have this problem of a timeout all the time from legal hosts, and it is causing a major issue for me, as these mails all whom receive legal responses ie user does not exist, etc, the sessions all timeout regardless. This needs to be resolved I cannot beleive that 30 or 40 mail servers have the sdame issues all the time.
  6. uwedegenhardt

    uwedegenhardt Member

    Hi Keith, is this issue solved ? I am experiencing the same !
    Uwe
  7. yeecheing

    yeecheing New Member

    I have the same error but without other error code.
    May I know how to find out the actual problem?