DOCUMENT:Q177867  20-MAR-1999  [exchange]
TITLE   :XCON: NDR Not Received When Sending to Bad PAB Entry
PRODUCT :Microsoft Exchange
PROD/VER:4.0 5.0 5.5
OPER/SYS:
KEYWORDS:

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The information in this article applies to:

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

When a Microsoft Exchange user sends a message to a recipient in his or her
Personal Address Book (PAB), the user does not receive a non-delivery report
(NDR) if the PAB entry is invalid. This problem only occurs in the following
circumstance:

1. The message has been addressed to an Exchange user in another Microsoft
   Exchange site whose address is in the originator's PAB. The PAB entry has
   become invalid either because they have been deleted from the system or their
   original site no longer exists in the Microsoft Exchange organization.

2. The connector that routes this message is a X.400 Connector configured as
   1984.

3. The connector does not have any Connected Sites information.

The message to the invalid PAB entry can be tracked by setting the X.400 Service
category of the MSExchangeMTA to Maximum logging in the Exchange Administrator
program. By looking for the 271 and 272 events in the Windows NT Event Viewer
Application log, you see that the message is sent to the destination Exchange
message transfer agent (MTA) successfully, a 271 event, then the resulting NDR
from this system is received, a 272 event, and finally the MTA passes this on to
the Exchange information store, another 271 event. However, the originator of
the message does not receive the NDR.

If you turn on maximum logging for the information store, specifically:

   MSExchangeISPriv/Transport Sending & Transport Delivering
   MSExchangeISPriv/Transport/General/<all categories>

you see the following error in the Event Log:

   Event ID : 2026
   Source : MS Exchange Private
   Type : Information
   Category : Transport
   Description : The delivery of a report failed due to error 00000BB8.
   The report has been deleted.

CAUSE
=====

The MTA was not correctly handling Distinguished Name (DN) addresses. The MTA
now checks these before sending and will NDR the message back to the originator
with the following diagnostic information:

   The recipient could not be transferred because it could not be
   downgraded.

WORKAROUND
==========

The workaround for this is to use versions of the MTA greater than or equal to
the following:

   Exchange 4.0 : 996.56
   Exchange 5.0 : 1459.72
   Exchange 5.5 : 2110.00

STATUS
======

Microsoft has confirmed this to be a problem in Microsoft Exchange Server
version 4.0. This problem has been corrected in the latest U.S. Service Pack for
Microsoft Exchange Server version 4.0. 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

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

Microsoft has confirmed this to be a problem in Microsoft Exchange Server version
5.5. This problem has been corrected in the latest U.S. Service Pack for
Microsoft Exchange Server version 5.5. 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

Additional query words: DN NDR 84 GWART X.500 one-off
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Keywords          :  
Technology        : kbExchangeSearch kbExchange500 kbExchange550 kbExchange400 kbZNotKeyword2
Version           : 4.0 5.0 5.5
Issue type        : kbbug
Solution Type     : kbfix

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