XCON: MTA Stops Processing Messages and Generates 9156 Events

ID: Q193894

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://www.microsoft.com/support/supportnet/overview/overview.asp

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.:

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.

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.

Keywords : exc55sp2fix
Version : WinNT:5.0,5.5
Platform : winnt
Issue type : kbbug