Users expierencing problem with email on GENESIS server...
Today some customers using our Linux-based services experienced an issue with duplicate emails in their INBOX. This issue seems to have been caused by a time mismatch. Engineering found the NTPd service stopped on the GENESIS server. Below is cPanel's description of how this kind of issue comes about:
1. Remote Server sends email "A" to cPanel server with Exim, Exim delays the email due to time difference but does not report back to sending server with success or failure.
2. Remote Server assumes that the email failed due to no response, re-queues email again for delivery as email "B" (a new transaction) to attempt again at a later time.
3. Exim finally delivers email A after time-change differential has passed
4. Remote Server attempts to resend email as email "B", hits the same issue of delay and re-queues email as email "C"
5. Remote Server and Exim are then stuck in a loop where the email sent is delayed in the Exim queue for the time differential, and the remote server attempts to resend the message. Each duplicate message is its own Exim transaction
CyberTec Engineering Services
Wednesday, April 14, 2021