Exim questions (unexpected disconnection and Connection reset by peer)

Phuturist

Verified User
Joined
Dec 30, 2018
Messages
22
I have been running Exim for a while but today an email coming from my server was bounced. The email was send using Gmail which has the SMTP configured and the Delivery Status Notification given by Gmail was "550 No such recipient here". As I am sure the address exists I looked at the logs and found the following.

Code:
2020-01-22 09:49:01 SSL_write: (from mail-oln040092068028.outbound.protection.outlook.com (EUR02-HE1-obe.outbound.protection.outlook.com) [40.92.68.28]) syscall: Connection reset by peer
2020-01-22 09:51:37 H=mail-io1-f54.google.com [209.85.166.54] X=TLS1.2:ECDHE-RSA-AES128-GCM-SHA256:128 CV=no F=<[email protected]> A=plain:[email protected] rejected RCPT <[email protected]>:
2020-01-22 09:51:37 H=mail-io1-f54.google.com [209.85.166.54] incomplete transaction (QUIT) from <[email protected]>

I also see message like this a lot that worry me.

Code:
2020-01-22 23:50:47 H=([78.83.182.112]) [78.83.182.112] incomplete transaction (connection lost) from <[email protected]>
2020-01-22 23:50:47 unexpected disconnection while reading SMTP command from ([78.83.182.112]) [78.83.182.112] (error: Connection reset by peer) D=2s

This is beyond my knowledge and I would appreciate if someone could explain what is going on.
 

Richard G

Verified User
Joined
Jul 6, 2008
Messages
8,956
Location
Maastricht
Just out of curiousity, I'm esperiencing this also a lot with outlook.com e-mails:
Code:
[40.92.89.57]) syscall: Connection reset by peer
 

Phuturist

Verified User
Joined
Dec 30, 2018
Messages
22
As far as I could tell it's because some Outlook servers are blacklisted on spam lists used by Directadmin / Exim. This causes the handshake to fail and resets the connection because the response is being blocked.

I added 40.92.0.0/15 to /etc/virtual/whitelist_hosts_ip and added outlook.com and outbound.protection.outlook.com and mail.protection.outlook.com to /etc/virtual/whitelist_domains which seems to have solved this. Maybe not the best solution but it works.
 
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