DOCUMENT:Q176489  22-OCT-2000  [exchange]
TITLE   :XCON: MTA Generates NDRs and Message Loops
PRODUCT :Microsoft Exchange
PROD/VER:WinNT:5.0
OPER/SYS:
KEYWORDS:

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The information in this article applies to:

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

After you restart a Microsoft Exchange Server computer that has been offline for
a few hours or days, the Message Transfer Agent (MTA) may start rejecting
messages, holding messages in the queues, or creating message loops. All of
these symptoms contribute to degraded system performance and slow mail flow. The
following error may occur:

   Event ID 200
   Source MSExchangeMTA
   Type Warning
   Category X.400 Service
   Description An error occurred while ASN.1 was decoding an object (dump
   reference 192). [limit exceeded on set of or sequence of 30464 2614
   1spdi 192 MTA XFER-IN 15 97] Event ID 2024 Source MSExchangeIS Private
   TypeError Category MTA Connections Description: Unable to access the
   object manager (OM) object from the Microsoft Exchange MTA for
   MH_T_ALTERNATE_RECIP_ALLOWED, MH_T_CONVERSION_LOSS_PROHIBITED, etc.

CAUSE
=====

This behavior can occur when the MTA Open Interval time is set too low. These
settings are located in a few places depending on the setup. The global setting
can be found by:

1. Opening the Microsoft Exchange Administrator program.

2. Highlight and expand the Exchange Site name.

3. Highlight the Configuration option.

4. Highlight MTA Site Configuration and select File, Properties.

5. Select the Messaging Defaults Tab.

The Administrator may also set the MTA Open Interval time on individual X400 and
Dynamic RAS connectors. The Open Interval Setting is located on each connector's
Override tabs on their respective property pages.

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

The Open Interval time is used to determine how long the MTA should wait before
attempting an association to another MTA. The default is 600 seconds, which
should suffice in most situations. The lowest value that can be entered is 15
seconds; however, if you set the value this low, the above problem will occur if
the MTA has to handle a large volume of messages (such as restarting after a
maintenance period). It is recommend that this setting is never below 30 seconds
on a LAN and 60 seconds on a RAS connection.

Additional query words: ndr stuck queue perfmon
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Keywords          :  
Technology        : kbExchangeSearch kbExchange500 kbZNotKeyword2
Version           : WinNT:5.0
Issue type        : kbbug
Solution Type     : kbfix

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