DOCUMENT:Q159181  19-DEC-1999  [exchange]
TITLE   :XCON: Duplicate Messages Received by MS Mail Recipients
PRODUCT :Microsoft Exchange
PROD/VER:winnt:4.0,5.0,5.5
OPER/SYS:
KEYWORDS:exc4 exc5 exc55

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The information in this article applies to:

 - Microsoft Exchange Server, versions 5.5, 4.0, 5.0 
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SYMPTOMS
========

Messages sent to Microsoft Mail recipients through the Microsoft Exchange
Internet Mail Connector (IMC) can result in duplicate messages. The sent and
recv logs show the message is received and delivered multiple times. The number
of duplicate copies received by an individual is equal to the number of
Microsoft Mail recipients that are on the recipient list.

CAUSE
=====

Any message received by the Exchange IMC has a responsibility flag set. However,
the Windows NT, OS/2, and MS-DOS Multitasking Message Transfer Agent (MMTA)
products do not understand the responsibility flag, and External delivers the
message to each Microsoft Mail recipient that it finds.

WORKAROUND
==========

To work around this problem:

 - If the originating system is a Sendmail V8 or IDA Sendmail, set the mail
   delivery flag to allow a single message for multiple recipients.

   -or-

 - Use of the Microsoft MSMI should also eliminate duplicate messages but this
   requires replacing existing instances of external with MSMI connectors.

STATUS
======

Microsoft has confirmed this to be a problem in External.exe version 3.5. A
supported fix is now available, but has not been fully regression-tested and
should be applied only to systems experiencing this specific problem. Unless you
are severely impacted by this specific problem, Microsoft recommends that you
wait for the next Service Pack that contains this fix. Contact Microsoft
Technical Support for more information.


MORE INFORMATION
================

For more information, see the Sendmail book published by O'Reilly and
Associates.

Additional query words: mailer

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Keywords          : exc4 exc5 exc55 
Technology        : kbExchangeSearch kbExchange500 kbExchange550 kbExchange400 kbZNotKeyword2
Version           : winnt:4.0,5.0,5.5

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