Results 1 to 2 of 2

Thread: 451 4.7.1 Service unavailable - try again later (in reply to end of DATA....

Hybrid View

  1. #1
    Join Date
    Sep 2005
    Rep Power

    Default 451 4.7.1 Service unavailable - try again later (in reply to end of DATA....

    Server version: 7.1.2_GA_3268.UBUNTU10_64 UBUNTU10_64 FOSS edition

    We are getting some emails returned as undeliverable by our server with the following message,

    host[xx.xx.xx.xx] said: 451
       4.7.1 Service unavailable - try again later (in reply to end of DATA
    My first guess was that the emails had unusually long attachements that was causing a timeout before the DATA section had completed. However people are reporting that their emails to us are bounced with a size less than 2MB.

    I put a watch on the zimbra.log for anything with the word "timeout" in it. There are lots of messages like...
    May 14 17:27:48 mail postfix/smtpd[17009]: timeout after END-OF-MESSAGE from localhost[]
    ...and a few like...
    May 14 05:57:31 mail postfix/smtpd[16856]: timeout after DATA (7008 bytes) from unknown[.....
    However none of these timeout messages involves one of the IP addresses involved in a sender who has confirmed they were getting their email bounced from us. There doesn't seem to be anything obvious in the logs when it happens, although I am still searching around the date/time of the rejections.

    Simply egrepping for "[^0-9]451[^0-9]" doesn't show anything except an unlrelated mention of the number "451".

    Our Zimbra server is running on a VSpere 5/SAS/SATA environment on a Dell 2950.

    I would appreciate some ideas on what might be causing these timeouts and where they would be reported if not in zimbra.log.

  2. #2
    Join Date
    Sep 2005
    Rep Power


    OK, now I've had some more time to look at the issue, I've found the occurance in the log files.

    May 14 11:06:11 mail postfix/cleanup[29709]: warning: milter inet: can't read SMFIC_HEADER reply packet header: Success
    May 14 11:06:11 mail postfix/cleanup[29709]: 4381A2017D3: milter-reject: END-OF-MESSAGE from[xx.xx.xx.xx]: 4.7.1 Service unavailable - try again later; from=<> to=<> proto=ESMTP helo=<>
    May 14 11:06:11 mail postfix/smtpd[27688]: disconnect from[xx.xx.xx.xx]
    I have found another thread regarding this issue.

    I have tried the solution suggested by FritzBrause,
    zmlocalconfig -e milter_thread_keep_alive_time=120
    zmlocalconfig -e milter_write_timeout=30
    zmcontrol restart
    Let's see if it helps.

Similar Threads

  1. message refused (in reply to end of DATA)
    By reza225 in forum Administrators
    Replies: 2
    Last Post: 02-03-2014, 10:06 AM
  2. [SOLVED] Lot of mails deferred
    By pigui in forum Administrators
    Replies: 17
    Last Post: 04-10-2012, 05:15 AM
  3. [SOLVED] Mailserver down when send file attach of 50Mb
    By ZMilton in forum Administrators
    Replies: 20
    Last Post: 04-10-2008, 11:44 AM
  4. Replies: 20
    Last Post: 03-18-2008, 05:37 AM
  5. Replies: 3
    Last Post: 07-19-2007, 02:00 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts