You receive NDR messages for some recipients when you send e-mail messages on an Exchange 2007-based server

When you send e-mail messages to some recipients, you receive non-delivery report (NDR) messages for these recipients.

This problem occurs if the following conditions are true:

• The Microsoft Exchange EdgeSync service is running on a server that is running Microsoft Exchange Server 2007.
• The Exchange 2007-based server is running the Hub Transport role.
• The blocked recipients list is configured on the Exchange 2007-based server.
• The recipients on the blocked recipients list are in a domain that is different from the Hub Transport server. Or, the recipients on the blocked recipients list are in the same domain (is a peer domain of the forest root domain) in which the Hub Transport server is located.

Note The NDR includes the following error message: This message indicates that the recipient is not valid. However, the recipient is not on the blocked recipient list.

This problem occurs because the Exchange EdgeSync service synchronizes only objects from the same domain tree. The Exchange EdgeSync service does not synchronize objects from other domain trees in the same forest. Recipients who are located in domains other than the Hub Transport server or outside the root domain tree are treated as unknown users.

To resolve this problem, install Update Rollup 4 for Exchange Server 2007 on the server that is running Exchange Server 2007. For more information about Update Rollup 4 for Exchange Server 2007, see the following Exchange Help topic: For more information about how to install the latest Exchange service pack or update rollup, see the following Exchange Help topic:

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

The Exchange EdgeSync service is the data synchronization service that runs on a Hub Transport server. The Exchange EdgeSync service is usually used for anti-spam purposes.

For more information about the Exchange EdgeSync service, visit the following Microsoft TechNet Web site:You can configure the blocked recipients list in the Exchange 2007 Management Console. To do this, follow these steps:

1. Open the Exchange 2007 Management Console.
2. Click Edge Transport, and then click Anti-Spam.
3. Right-click Recipient Filtering, and then click Properties.
4. Click Blocked Recipients, and then click to select the Block messages sent to recipients not listed in the GAL check box.

For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base: For more information about the new naming schema for Exchange Server software update packages, click the following article number to view the article in the Microsoft Knowledge Base: