XFOR: Slow Processing of Internet Messages with MIME Bodyparts

ID: Q173343

The information in this article applies to:

Microsoft Exchange Server, version 5.0

SYMPTOMS

When you receive messages from the Internet with nested MIME (Multipurpose Internet Mail Extensions) bodyparts, the conversion process for the MIME bodyparts may cause the slow delivery of these messages. As the messages are delivered, the server will require a large amount of system resources, especially memory. If a large number of these messages are received at the same time, the system may report it is running low on virtual memory.

CAUSE

MIME bodyparts within a message item can be nested. If the nesting level is high, the conversion process requires more and more resources to decode the entire message. A single message with a MIME bodypart nested to 700 levels can take up to 10 minutes to process.

STATUS

Microsoft has confirmed this to be a problem in 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:

SERVPACK

MORE INFORMATION

Because it is unlikely that valid messages will be nested to much more than 30 levels, the Microsoft Exchange information store should not try to process messages beyond this point. A new registry key has been added in the fix referred to in the STATUS section above that limits the amount of nesting the information store will process. The registry switch is at:


HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeIs\Parame
tersSystem\InternetContent\LimitNestingLevels

If this entry is missing, a default of 30 nested MIME bodyparts will be processed per message. Specifying a DWORD value will prevent messages from being processed with nested bodyparts above that level. A value of zero will prevent all messages containing MIME bodyparts from being processed.

Additional query words: 5.00 SP1 IMS IMC CONVERSION

Keywords : kbusage kbbug5.00 kbfix5.00.sp2 XFOR
Version : winnt:5.0
Platform : winnt
Issue type :