Emails to Greylisting servers not getting retried

W

WadeO

Verified User
Joined
Jun 22, 2023
Messages
8
Hi

I am a Hosting Reseller and for over 3 months my Hosting provider has been having an issue with emailing to people that have Greylisting activated on their Servers.
They have been trying different configs without any resolution.

The email gets defer (-44) then gets removed from the queue without retrying so my clients are complaining emails are not getting sent works fine if they email 5mins later but the initial email they have no way to know that it was never sent, this is the log. Have had endless nights trying to sort this problem out and any help or to point me in the right direction would be appreciated.

Code: 
2023-06-07 10:59:12 cwd=/var/spool/exim 3 args: /usr/sbin/exim -Mc 1q6p0a-00Cv4z-2A
2023-06-07 11:26:10 cwd=/root 3 args: exim -Mrm 1q6p0a-00Cv4z-2A
2023-06-07 10:59:12 1q6p0a-00Cv4z-2A <= [email protected] H=(d1.my-server-panel.com) [127.0.0.1] P=esmtpa A=login:[email protected] S=832 [email protected] T="Email problem" from <[email protected]> for [email protected]
2023-06-07 10:59:16 1q6p0a-00Cv4z-2A H=za-smtp-inbound-1.mimecast.co.za [41.74.197.210]: SMTP error from remote mail server after RCPT TO:<[email protected]>: 451 Internal resource temporarily unavailable - https://community.mimecast.com/docs/DOC-1369#451 [KJtMKLc0Pp20lQ-zYpsuYQ.za54]
2023-06-07 10:59:20 1q6p0a-00Cv4z-2A H=za-smtp-inbound-1.mimecast.co.za [41.74.197.201]: SMTP error from remote mail server after RCPT TO:<[email protected]>: 451 Internal resource temporarily unavailable - https://community.mimecast.com/docs/DOC-1369#451 [oCC_P2s_O7KLm1m8eU8h-w.za30]
2023-06-07 10:59:25 1q6p0a-00Cv4z-2A H=za-smtp-inbound-1.mimecast.co.za [41.74.193.210]: SMTP error from remote mail server after RCPT TO:<[email protected]>: 451 Internal resource temporarily unavailable - https://community.mimecast.com/docs/DOC-1369#451 [FlPzeNUhN-yHTnBNYAfdDw.za117]
2023-06-07 10:59:29 1q6p0a-00Cv4z-2A == [email protected] R=lookuphost T=remote_smtp defer (-44) H=za-smtp-inbound-1.mimecast.co.za [41.74.193.201]: SMTP error from remote mail server after RCPT TO:<[email protected]>: 451 Internal resource temporarily unavailable - https://community.mimecast.com/docs/DOC-1369#451 [wndm8QkfPnK4hgP6gW5qJQ.za13]
2023-06-07 11:26:10 1q6p0a-00Cv4z-2A removed by root
2023-06-07 11:26:10 1q6p0a-00Cv4z-2A Completed
 
You need to ask mimecast why they discard emails, if they didn't describe it in their error message

Customer Community

community.mimecast.com community.mimecast.com
it's their own filter/policy.
 
Zhenyapan said:
You need to ask mimecast why they discard emails, if they didn't describe it in their error message

Customer Community

community.mimecast.com community.mimecast.com
it's their own filter/policy.
Click to expand...
This is to all greylisting servers not just MimeCast. The right way is for the queue to retry the message on a 451 error and not remove it. But it never gets retried just removed. If it just retried the message anytime after 5 mins the email would go through fine due to Greylisting Policies.
 
in such case - configure your retry policy:

32. Retry configuration

Exim is a message transfer agent (MTA) developed at the University of Cambridge for use on Unix systems connected to the Internet.
www.exim.org
 
This is the retry configuration


Code: 
##################################################################################
# RETRY CONFIGURATION
##################################################################################
#EDIT#65:
# Domain               Error       Retries
# ------               -----       -------
begin retry
*                      quota
*                      *           F,2h,15m; G,16h,1h,1.5; F,4d,8h
# End of Exim 4 configuration
 
Richard G said:
Isn't the ip of the server blacklisted maybe?
Click to expand...
IP is fine. This is how Greylisting works.
451 Internal resources are temporarily unavailableThe sending mail server is subjected to Greylisting. This requires the server to retry the connection between one minute and 12 hours.

The Greylisting Process​

Greylisting looks at the following pieces of information for the delivery attempt:

  • IP address of the MTA
  • Envelope sender address
  • Envelope recipient address
With this information, we have a unique relationship for that particular SMTP session:

  • If we've never seen this information before, a server busy status (451 Resource is Temporarily Unavailable) is issued. This is a temporary failure and is maintained for 60 seconds, forcing the sending server to queue and retry.
  • A correctly configured MTA always attempts to retry the message's delivery. If the MTA retries after 60 seconds and before the 12-hour upper limit, the message is accepted.
  • If the message is not retried in this 12-hour period, an entry is logged in the Rejection Viewer as "Sender Failed to Retry" (12 hours after the initial attempt). See the Message Center: Rejected and Deferred Messages page for further details.
  • If the sending MTA attempts again after 12 hours from the initial attempt, the greylisting process restarts.
Note:By default an Exchange server retries to send a message every 10 minutes until the message retries expire.
 
So it should if configured correctly retry the message after the retry interval. I don't know if it's because of the multiple IPs that are failing, then the last one gets deferred?


Markdown (GitHub flavored): 
2023-06-07 10:59:16 1q6p0a-00Cv4z-2A H=za-smtp-inbound-1.mimecast.co.za [41.74.197.210]: SMTP error from remote mail server after RCPT TO:<[email protected]>: 451 Internal resource temporarily unavailable - https://community.mimecast.com/docs/DOC-1369#451 [KJtMKLc0Pp20lQ-zYpsuYQ.za54]
2023-06-07 10:59:20 1q6p0a-00Cv4z-2A H=za-smtp-inbound-1.mimecast.co.za [41.74.197.201]: SMTP error from remote mail server after RCPT TO:<[email protected]>: 451 Internal resource temporarily unavailable - https://community.mimecast.com/docs/DOC-1369#451 [oCC_P2s_O7KLm1m8eU8h-w.za30]
2023-06-07 10:59:25 1q6p0a-00Cv4z-2A H=za-smtp-inbound-1.mimecast.co.za [41.74.193.210]: SMTP error from remote mail server after RCPT TO:<[email protected]>: 451 Internal resource temporarily unavailable - https://community.mimecast.com/docs/DOC-1369#451 [FlPzeNUhN-yHTnBNYAfdDw.za117]
2023-06-07 10:59:29 1q6p0a-00Cv4z-2A == [email protected] R=lookuphost T=remote_smtp defer (-44) H=za-smtp-inbound-1.mimecast.co.za [41.74.193.201]: SMTP error from remote mail server after RCPT TO:<[email protected]>: 451 Internal resource temporarily unavailable - https://community.mimecast.com/docs/DOC-1369#451 [wndm8QkfPnK4hgP6gW5qJQ.za13]
 
Last edited:
I provided you manual, you need to configure it to retry on 451 error (or any another you want). Not every reject will put email to retry queue.
 
Zhenyapan said:
I provided you manual, you need to configure it to retry on 451 error (or any another you want). Not every reject will put email to retry queue.
Click to expand...
I did suggest that but then get this error

Code: 
##################################################################################
# RETRY CONFIGURATION
##################################################################################
# Domain               Error       Retries
# ------               -----       -------
begin retry
*                      quota
*                      rcpt_451    F,1h,5m
*                      *           F,2h,15m; G,16h,1h,1.5; F,4d,8h
# End of Exim 4 configuration

Markdown (GitHub flavored): 
2023-06-07 07:10:32 cwd=/var/spool/exim 3 args: /usr/sbin/exim -Mc 1q6lRI-007NOT-1A
2023-06-07 07:10:51 cwd=/var/spool/exim 7 args: /usr/sbin/exim -t -oem -oi -f <> -E1q6lRI-007NOT-1A
2023-06-07 07:10:32 1q6lRI-007NOT-1A <= [email protected] H=(d1.my-server-panel.com) [127.0.0.1] P=esmtpa A=login:[email protected] S=761 [email protected] T="Mimecast admin" from <[email protected]> for [email protected]
2023-06-07 07:10:38 1q6lRI-007NOT-1A H=za-smtp-inbound-1.mimecast.co.za [41.74.193.201]: SMTP error from remote mail server after RCPT TO:<[email protected]>: 451 Internal resource temporarily unavailable - https://community.mimecast.com/docs/DOC-1369#451 [5PnxqRiNNo-kiL0eKABq6g.za55]
2023-06-07 07:10:42 1q6lRI-007NOT-1A H=za-smtp-inbound-1.mimecast.co.za [41.74.197.201]: SMTP error from remote mail server after RCPT TO:<[email protected]>: 451 Internal resource temporarily unavailable - https://community.mimecast.com/docs/DOC-1369#451 [2Eka9P2pMi6UFwVMFUl2XA.za28]
2023-06-07 07:10:46 1q6lRI-007NOT-1A H=za-smtp-inbound-1.mimecast.co.za [41.74.193.210]: SMTP error from remote mail server after RCPT TO:<[email protected]>: 451 Internal resource temporarily unavailable - https://community.mimecast.com/docs/DOC-1369#451 [lknbEATPMtuZUYpmAuHHCA.za83]
2023-06-07 07:10:51 1q6lRI-007NOT-1A == [email protected] R=lookuphost T=remote_smtp defer (-44) H=za-smtp-inbound-1.mimecast.co.za [41.74.197.210]: SMTP error from remote mail server after RCPT TO:<[email protected]>: 451 Internal resource temporarily unavailable - https://community.mimecast.com/docs/DOC-1369#451 [wFxQ8zHbPXScAnTIqU8hOA.za72]
2023-06-07 07:10:51 1q6lRI-007NOT-1A ** [email protected]: retry timeout exceeded
2023-06-07 07:10:51 1q6lRI-007NOT-1A Completed
2023-06-07 07:10:51 1q6lRb-007Nmu-0A <= <> R=1q6lRI-007NOT-1A U=mail P=local S=2576 T="Mail delivery failed: returning message to sender" from <> for [email protected]
2023-06-07 07:10:51 1q6lRb-007Nmu-0A => test <[email protected]> F=<> R=virtual_user T=dovecot_lmtp_udp S=2756 C="250 2.0.0 <[email protected]> yKcTBFsRgGQuqRoACWC2WQ Saved"
2023-06-07 07:10:51 1q6lRb-007Nmu-0A Completed


Get 2023-06-07 07:10:51 1q6lRI-007NOT-1A ** [email protected]: retry timeout exceeded
 
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