DOCUMENT:Q193894  20-MAY-2002  [exchange]
TITLE   :XCON: MTA Stops Processing Messages and Generates 9156 Events
PRODUCT :Microsoft Exchange
PROD/VER:WinNT:5.0,5.5
OPER/SYS:
KEYWORDS:exc55sp2fix

======================================================================
-------------------------------------------------------------------------------
The information in this article applies to:

 - Microsoft Exchange Server, versions 5.0, 5.5 
-------------------------------------------------------------------------------


SYMPTOMS
========

When a network connection goes down and the message transfer agent (MTA) is
unable to send mail over an X.400 connector, the MTA leaks 1 CB if the number of
connection attempts issued is more than 1. Eventually, the MTA will report 9156
errors in the application event log and a backlog of messages will begin to
build.

CAUSE
=====

This problem is caused by a bug in the MTA Winsock code.

RESOLUTION
==========

Exchange Server 5.0
-------------------

A supported fix that corrects this problem is now available from Microsoft, but
has not been fully regression tested and should be applied only to systems
experiencing this specific problem. If you are not severely affected by this
specific problem, Microsoft recommends that you wait for the next Microsoft
Exchange Server version 5.0 service pack that contains this fix.

To resolve this problem immediately, contact Microsoft Product Support Services
to obtain the fix. For a complete list of Microsoft Product Support Services
phone numbers and information on support costs, please go to the following
address on the World Wide Web:

   http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS

The English version of this fix should have the following file attributes or
later:

   Component: Message Transfer Agent (MTA)

   File Name      Version
   --------------------------
   Address.dll    5.0.1461.66
   Dbserver.sch   5.0.1461.66
   Dcprods.cat    5.0.1461.66
   Ems_rid.dll    5.0.1461.66
   Emsmta.exe     5.0.1461.66
   Infoplog.cfg   5.0.1461.66
   Infotlog.cfg   5.0.1461.66
   Infoxlog.cfg   5.0.1461.66
   Mmiext.dll     5.0.1461.66
   Mtacheck.exe   5.0.1461.66
   Mtamsg.dll     5.0.1461.66
   P2.xv2         5.0.1461.66
   P3.tpl         5.0.1461.66
   P772.tpl       5.0.1461.66
   X400om.dll     5.0.1461.66
   X400omv1.dll   5.0.1461.66


Exchange Server 5.5
-------------------

To resolve this problem, obtain the latest service pack for Exchange Server
version 5.5. For more information, please see the following article in the
Microsoft Knowledge Base:

   Q191014 XGEN: How to Obtain the Latest Exchange Server 5.5 Service Pack


The English version of this fix should have the following file attributes or
later:

   Component: Message Transfer Agent (MTA)

   File Name     Version
   -----------------------
   Dbserver.sch   5.5.2410.0
   Dcprods.cat    5.5.2410.0
   Ems_rid.dll    5.5.2410.0
   Emsmta.exe     5.5.2410.0
   Info4log.cfg   5.5.2410.0
   Infodlog.cfg   5.5.2410.0
   Infollog.cfg   5.5.2410.0
   Infotlog.cfg   5.5.2410.0
   Mtacheck.exe   5.5.2410.0
   Mtamsg.dll     5.5.2410.0
   P2.xv2         5.5.2410.0
   X400om.dll     5.5.2410.0
   X400omv1.dll   5.5.2410.0


STATUS
======

Microsoft has confirmed this to be a problem in Microsoft Exchange Server
versions 5.0 and 5.5.

WORKAROUND
==========

If you are not able to install the latest hotfix or service pack, perform the
following steps on the bridgehead servers logging the 9156 events, and on the
remote X.400 bridgehead servers.:

1. Increase the TCP/IP control blocks in the registry located in the following
   key:

   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeMTA\ 
   Parameters
  

   NOTE: The above is one path; it has been wrapped for readability.

   To do so, use the following equation:

   ((X400 connectors * 10) + 10)

   The results should be placed in the key as decimal.

2. On the Override property page of every X.400 connector, in the Associations
   section, increase the Disconnect value. The default is 120; increase the
   value to at least 360. This value can be increased or decreased as necessary
   to work around the problem.

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Keywords          : exc55sp2fix 
Technology        : kbExchangeSearch kbExchange500 kbExchange550 kbZNotKeyword2
Version           : WinNT:5.0,5.5
Issue type        : kbbug
Solution Type     : kbfix

=============================================================================

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