DOCUMENT:Q176455  14-MAR-1999  [exchange]
TITLE   :XADM: NDR When Attempting to Send to Large Number of Recipients
PRODUCT :Microsoft Exchange
PROD/VER:WINDOWS:5.0
OPER/SYS:
KEYWORDS:kbusage

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The information in this article applies to:

 - Microsoft Exchange Server, version 5.0 
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SYMPTOMS
========

If you attempt to send a message to 10 or more recipients or send a message that
is larger than 4,096 bytes, the message may appear in the Outbox for an
unusually long time and then you may receive a non- delivery report (NDR) that
contains the following text:

   Unable to deliver the message due to a recipient problem

CAUSE
=====

When data is written to the message transfer agent (MTA), a 16-KB buffer is
used. If the server attempts to transfer more than 16 KB at a time, you may
experience the symptoms described above.

When a message is addressed to fewer than 10 recipients or is 4,096 bytes or
smaller, one recipient descriptor is transferred at a time. In this case, the
server rarely exceeds the 16-KB buffer limit for writing data to the MTA.
However, when a message is addressed to 10 or more recipients or is larger than
4,096 bytes, ten recipient descriptors are transferred at a time instead of one.
When this occurs, the server frequently exceeds the 16- KB buffer limit.

STATUS
======

Microsoft has confirmed this to be a problem in Microsoft Exchange Server
version 5.0. This problem has been corrected in the latest U.S. Service Pack for
Microsoft Exchange Server version 5.0. For information on obtaining the Service
Pack, query on the following word in the Microsoft Knowledge Base (without the
spaces):

   S E R V P A C K


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Keywords          : kbusage 
Technology        : kbExchangeSearch kbExchange500 kbZNotKeyword2
Version           : WINDOWS:5.0
Issue type        : kbbug
Solution Type     : kbfix

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