XCON: X.400 Messages with Attachments May Cause 100% CPU Usage by the MTA

• Microsoft Exchange Server, version 5.0

SYMPTOMS

Performance Monitor shows a constant 100 percent CPU utilization caused by the message transfer agent (MTA). The computer running Microsoft Exchange Server still responds to user input, but does so slowly. The service MSExchangeMTA cannot be stopped using either Control-Panel Services or the "Net Stop" command.

CAUSE

The MTA may cause 100 percent CPU usage when receiving a specific message. The message must originate from Microsoft Mail and be sent via its X.400 Gateway. It can either be sent directly to the Exchange Server MTA or routed through an intermediate third-party X.400 system, such as MAIL.X, to Exchange Server. Additionally, the message has to contain an attachment. On processing the attachment, the MTA enters an infinite loop, thus causing 100 percent CPU usage.

RESOLUTION

To resolve this problem, obtain the fix described below or wait for the next Microsoft Exchange Server 5.0 service pack.

The fix installs the following files in the following folders:

   File           Location(s)
   --------------------------
   Address.dll    Exchsrvr\Bin (See note below)
   Dbserver.sch   Exchsrvr\Mtadata
   Dcprods.cat    Exchsrvr\Bin
                  Exchsrvr\Mtadata
   Ems_rid.dll    Exchsrvr\Bin
   Emsmta.exe     Exchsrvr\Bin
   Infotlog.cfg   Exchsrvr\Mtadata
   Infoxlog.cfg   Exchsrvr\Mtadata
   Mapi32.dll     Winnt\System32
   Mmiext.dll     Exchsrvr\Bin (See note below)
   Mtacheck.exe   Exchsrvr\Bin
   Mtamsg.dll     Exchsrvr\Res
   P2.xv2         Exchsrvr\Bin
                  Exchsrvr\Mtadata
   P3.tpl         Exchsrvr\Mtadata
   P772.tpl       Exchsrvr\Mtadata
   X400om.dll     Exchsrvr\Bin
   X400omv1.dll   Exchsrvr\Bin (See note below) 

Notes

• If the Microsoft Mail Connector is installed on the server, you should manually copy the Address.dll and X400omv1.dll files to the Exchsrvr\Connect\Msmcon\Bin folder after applying the fix.



• If the Internet Mail Service is installed on the server, you should manually copy the Address.dll and X400omv1.dll files to the Exchsrvr\Connect\Msexcimc\Bin folder after applying the fix.



• If the Admin.exe utility is installed in a folder on the server other than the Exchsrvr\Bin folder, you should manually copy the Mmiext.dll file to the folder in which Admin.exe is installed after applying the fix.

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

MORE INFORMATION

The problem described in this article was introduced with an Exchange Server 5.0 post SP1 hotfix. Only MTA versions with build numbers 1459.17 and higher will show the above-described behavior.

Keywords : kbbug5.00 kbfix5.00.sp2 XCON
Version : WINDOWS:5.0
Platform : WINDOWS
Issue type : kbbug