Exchange blocking duplicate messages?

S Mohan smohan at VSNL.COM
Sat Oct 4 04:30:13 IST 2003

I've seen this being followed for POP access by Outlook/OE where the
messages are not deleted from the server. Maybe Exchange follows that for
SMTP too to avoid duplicate messages.


-----Original Message-----
From: MailScanner mailing list [mailto:MAILSCANNER at JISCMAIL.AC.UK]On
Behalf Of Hirsh, Joshua
Sent: Friday, October 03, 2003 7:55 PM
Subject: Exchange blocking duplicate messages?

Hey all,

 Has anyone run into the case where an Exchange 5.5 server will block
messages with the same Message-ID field? In my case, if I release a message
from the quarantine, some users will never get it. It appears that it's
because Exchange ignores the message since it already received one with the
same Message-ID (which was sent notifying the user that the attachment was

 I was able to reproduce it by manually sending SMTP commands to Exchange
and sent a message with the same Message-ID a few times. In all cases, only
the first one went through.

 It's definately more of an Exchange issue, but I'm hoping some of you might
have run into this before :)


More information about the MailScanner mailing list