If you configure Exchange Server 2007 for auto-reply on a public address, and the reply is sent to an address that also has auto-reply or out-of-office-auto-reply, then Exchange Server will receive a new message, same from-address, and will again send an auto-reply. This can go on forever and can potentially lead to a DoS situation.
How can I prevent multiple sending of auto-reply to the same address, preferably in a given timeframe (to prevent legitimate multiple mails to be treated incorrectly), using Exchange Server 2007?
Our XS hosting provider says it cannot be done, but that strikes me as odd.
I admit I'm no expert at this, but why it would do that is beyond me. I haven't had an Exchange installation do that as far as I recall, it will send the auto-reply once per sender. However, the end-user could with Outlook set up a manual rule that does that (or perhaps this Outlook 2000 KB about orphaned rules causing this is helpful).
Exchange can also be configured to not allow auto-reply outside the organisation at all regardless of user-configured rules, which may be seen as a good practice.
Out of office will only answer once. If you do an Auto-reply, you could end up with an mail storm situation like you are describing.
In your auto-reply logic - be it a vbscript or rule - try to add an exclusion for a subject with "RE: " in it. This would prevent the auto-reply from going out on an incoming reply to any message you send out.
Eventually, the solution proved to be rather trivial: add the
Precedence: BULKheader to the e-mail (as is common with news letters and such) and replies will not end up in a mail-loop, because they are ignored.I found this in the general guideline of mail on bulkmail.