Setup: Exchange server is used as MTA (accepting messages sent over SMTP).
Problem: when there are several messages from the same From: and same To:, sent in quick succession (several times a second - these are automated alerts from monitoring software), same Message-ID is assigned to several messages and some of them are dropped by Exchange as duplicates.
Sender is not receiving any error code from MTA. Messages are discarded silently.
Is this a known behavior, and how it should be handled? Generating Message-ID on sender side is out of question (there's no control over that). AFAIK, MTA inserts Message-ID header if that is missing.
Thanks