During this past weekend we had a fairly long maintenance period on a
couple of our Exchange servers and found that some messages coming
from outside of Exchange environment would get bounced back to the
relay server and eventually be deleted with a NDR. I was hoping that
someone may have a solution for this.
Here is the configuration for our Exchange environment.
- We have 3 Exchange servers.
- All incoming email arrives via a PostFix relay server which uses DNS
round robin; MX records point to all three servers.
In this example, what happened was we had two of our AMERICAS servers
offline for maintenance. It was reported to us that some expected
mail that was sent from the internet was never received from the
server which was down for maintenance. I seached for the message in
Message Tracking and discovered the message was bounced between the
online server and the relay. Eventually the message was deleted and a
NDR was sent. For the handful of messages I tracked, it varied from
bouncing back and forth from 2-4 hours and the amount of bounces
varied from around 10-30 bounces.
So the questions are:
- Why doesn't the messages queue up on the online Exchange server?
- Is there a way to configure Exchange not to give up so quickly?
The only thing I can think of that may resolve this is disable Smart
Host before our downtime. Unfortunately I would need a downtime to
test this, we have a lab but we don't have a relay server in our lab
to test this.
Thanks.
-Gene