A signed or encrypted message that contains an attachment takes a long time to be delivered from a Windows 2000-based computer

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Consider the follow scenario:
  • You are using a Microsoft Windows 2000-based computer.
  • You use the Defense Messaging System (DMS) program to send a signed or encrypted message to a Simple Mail Transfer Protocol (SMTP) address.
  • The message contains an attachment that is larger than 500 KB.
In this scenario, the message takes a long time to be delivered to the recipient.
DMS uses the XEXCH50 command to relay certain message properties, such as envelope, message, and recipient properties. The XEXCH50 command is a Microsoft Exchange extension that is supported by SMTP. An XEXCH50 command that has received a success type response is then followed by a binary large object (BLOB) of variable size.

This problem occurs because signed or encrypted messages that contain attachments that are larger than 500 KB create large BLOBs. These BLOBs block the SMTP route for a short time.

Hotfix information

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, submit a request to Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site: Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.


No prerequisites are required.

Restart requirement

You do not have to restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any other hotfixes.

File information

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.
   Date         Time   Version            Size    File name   --------------------------------------------------------------   22-Aug-2003  10:32  5.0.2195.6808     322,320  Aqueue.dll          22-Aug-2003  10:32  5.0.2195.6808      67,856  Mailmsg.dll         22-Aug-2003  10:32  5.0.2195.6808      38,672  Ntfsdrv.dll         22-Aug-2003  10:32  5.0.2195.6810     444,688  Smtpsvc.dll
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
More information
For more information, click the following article numbers to view the articles in the Microsoft Knowledge Base:
816915 New file naming schema for Microsoft Windows software update packages
824684 Description of the standard terminology that is used to describe Microsoft software updates

Article ID: 827551 - Last Review: 11/02/2013 17:03:00 - Revision: 3.0

Microsoft Windows 2000 Server, Microsoft Windows 2000 Professional Edition, Microsoft Windows 2000 Advanced Server

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