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Exim retry times after being greylisted seems to be random

Discussion in 'E-mail Discussion' started by Gino Viroli, Apr 23, 2019.

  1. Gino Viroli

    Gino Viroli Well-Known Member

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    In my "WHM > Server Configuration > Tweak Settings" the "Email delivery retry time" is set to 15 m (default)

    But when I look at "WHM > Email > Mail Delivery Reports", I see retry times that sometimes happen after couple of minutes and other time after 15 minutes.

    See the screenshot below; it tried to send at 1:00:01 AM and then retried at 1:02:01 AM (after only few minutes, instead of waiting 15 minutes) o_O

    retres-aftre-2-min.png


    Later on it worked correctly, it retried twice (at 12:17 and 12:32) after 15 minutes each, see screenshot:

    retries-afer-15m.png
     
    #1 Gino Viroli, Apr 23, 2019
    Last edited: Apr 23, 2019
  2. keat63

    keat63 Well-Known Member

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    Whilst I can't comment on the problem you are facing, I personally feel that Greylisting is flawed, and probably not the best solution to fight spam.

    Big corporations could have many IP addresses for thier mailservers.

    A mail exchange tries to send your server a genuine email, this IP is greylistyed for 15 minutes.
    The same mail exchange tries again in 15 minutes, but this time uses a different IP address, this IP is then greylisted.
    And on it goes.

    We had some emails taking many many hours to arrive.
     
  3. Gino Viroli

    Gino Viroli Well-Known Member

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    Here it's our server sending out an email and the recipient's server putting the message in greylist and asking our server to retry; so our server retries to send the message, but instead of retrying after 15 minutes, it seems to retry after few minutes.
     
  4. keat63

    keat63 Well-Known Member

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    I'm not 100% certain it works this way, however, i'm pretty sure someone with more knowledge will comment shortly

    When a mail server greylists your server, it doesn't send a message to your server and say 'come back in 15 minutes'
    I believe what happens, is the other server will just reject any attempts to deliver from your IP for 15 minutes.
    Your server can retry as many times as it likes, but the one at the other end is blocking you for 15 minutes.

    I'm no expert, but pretty sure, the behavour that your describing from your server is normal, and known as MTA retry.
     
  5. Infopro

    Infopro cPanel Sr. Product Evangelist Staff Member

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  6. Gino Viroli

    Gino Viroli Well-Known Member

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    Yes but the MTA retry is supposed to retry after 15 minutes (or whatever you set in "WHM > Server Configuration > Tweak Settings > Email delivery retry time").
    In my original post I showed a screenshot that proves that EXIM retries after few minutes instead of wating for 15 minutes.

    This documentation would be useful if I wanted to turn on Greylisting on my incoming mail.
    My issue here is not for incoming mail, but for outgoing mail from my EXIM mail server to another erver that has a sort of Graylisting service active, and my EXIM server instead of retrying after 15 minutes retries to send after few minutes.
     
  7. cPanelLauren

    cPanelLauren Forums Analyst II Staff Member

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    Exim will retry after the first minute every fifteen minutes:

    Code:
    This single retry rule applies to all domains and all errors. It specifies
    # retries every 15 minutes for 2 hours, then increasing retry intervals,
    # starting at 1 hour and increasing each time by a factor of 1.5, up to 16
    # hours, then retries every 8 hours until 4 days have passed since the first
    # failed delivery.

    So you attempt to send, it fails and within 1 minute it will try again and the retry time afterwards will be every 15 minutes for 2 hours.
     
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  8. Gino Viroli

    Gino Viroli Well-Known Member

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    So is it normal behaviour?
    If yes this thread is solved.
     
  9. cPanelLauren

    cPanelLauren Forums Analyst II Staff Member

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