You receive an NDR message after you send an e-mail message that contains a .zip file attachment by using an Exchange 2007 Edge server

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Article ID: 936734 - View products that this article applies to.
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After you send an e-mail message by using a Microsoft Exchange Server 2007 Edge server, you receive a non-delivery report (NDR) message that includes the following information:
550 5.7.1 Message rejected due to unacceptable attachments
This problem occurs if the following conditions are true:
  • The e-mail message contains a .zip file attachment.
  • The Attachment Filtering agent is enabled on the Exchange 2007 Edge server.
If you enable tracing for Exchange 2007, an exception exists. This exception indicates that the .zip file attachment is invalid. However, you can correctly open the attached .zip file.


This problem occurs because the Attachment Filtering agent cannot correctly parse certain .zip files. In these .zip files, the compressed size is not computed and then set before the file data.


To resolve this problem, install Update Rollup 5 for Exchange Server 2007. For more information about Update Rollup 5 for Exchange Server 2007, see the following Exchange Help topic:
Description of Update Rollup 5 for Exchange Server 2007
For more information about how to install the latest Exchange service pack or update rollup, see the following Exchange Help topic:
How to Obtain the Latest Service Pack or Update Rollup for Exchange 2007


Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.


Article ID: 936734 - Last Review: October 30, 2007 - Revision: 1.5
  • Microsoft Exchange Server 2007 Enterprise Edition
  • Microsoft Exchange Server 2007 Standard Edition
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