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zeratul021
Asked: 2011-09-18 07:03:15 +0800 CST

Postfix - delay mail processing

  • 772

is there a way to configure delay with which emails will be processed by postfix? What I'm aiming for is e.g. 5 minute lag between receiving mail from MUA and transferring it to mailbox or other MTA.

Thanks.

postfix

3 Answers

  1. This functionally should be implemented in the MUA. If you have a webmail you can install a plugin implementing this function. There is an extension available for Thunderbird. If a user sends an email and later changes her mind then she can cancel herself. I see no other way. Making nasty hacks on the server will just make things worse if one does not know all the answers already.

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  2. There is a way but it is such a stupid thing that I only provide the steps.

    Put this into your recipient_restrictions: recipient_restrictions = ..., static:HOLD, ... Then you will get an output of postqueue -p where all mails in hold-queue are marked with an ! (exclamation mark) and the arrival date. Use a cron-job and a script to parse and examine this output. If a mail is longer than x minutes in the queue you can reinject it to the Postfix delivery process by issuing a postsuper -H [queue_id]. The [queue_id] is in the first column of postqueue -p.

    And please don't ask for the script to automate this!

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  3. Best Answer

    You could pretty easily do this by specifying a new master transport in the smtpd section of main.cf:

    smtpd_recipient_restrictions = check_policy_service unix:private/sleep_delay, permit_mynetworks, reject_unauth_destination

    Then in master.cf:

    # ==========================================================================
# service type  private unpriv  chroot  wakeup  maxproc command + args
#               (yes)   (yes)   (yes)   (never) (100)
# ==========================================================================
sleep_delay  unix  -       n       n       -       -       spawn
        user=nobody argv=/usr/bin/perl /path/to/your_script

    In /path/to/your_script, just have it sleep(X) and exit(0). You can use this script/config as an example of how to implement external script interaction with postfix:

    http://www.howtoforge.com/postfix_spf

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