Topic Last Modified: 2010-02-18

The Microsoft Exchange Server 2010 Management Pack for System Center Operations Manager monitors the Windows Application log on computers running Exchange 2010 and generates this alert when the events specified in the following Details table are logged.

To learn more about this alert, in Operations Manager, do one or more of the following:


Product Name


Product Version

14.0 (Exchange 2010)

Event ID


Event Source


Alert Type


Rule Path

Microsoft Exchange Server/Exchange 2010/Common Components/Hub Transport and Edge Transport/Transport

Rule Name

The topology doesn't have a route to the Active Directory site in the routing tables.


This Error event indicates that the Microsoft Exchange Server 2010 transport routing engine can't calculate a route to the target Active Directory site. Because no route is available, the messages will be delivered to the Unreachable queue. This event may occur when one of the following conditions is true:

  • The specified Active Directory site is not included in any IP site links.

  • The IP site link for this Active Directory site is not configured correctly.

  • The Active Directory site is not configured correctly.

  • There are no Hub Transport servers located in the Active Directory site.

User Action

To resolve this error, do one or more of the following:

  • Verify that the specified Active Directory site is included in an IP site link.

  • If the specified Active Directory site was created recently, this error can be caused by replication latency. The affected messages will be resubmitted to the categorizer and rerouted when the routing tables are updated.

  • Verify that the Active Directory site that is specified in the error message text contains at least one Hub Transport server. If the Active Directory site already contains a Hub Transport server, make sure that it is reachable on the network.

  • Review other related Error and Warning events in the Application log. These related events may help you find the root cause of this error.

  • If the recommended steps do not resolve this error, contact Microsoft Customer Support Services. For more information about how to contact support, visit the Microsoft Help and Support Web site.

For More Information

If you are not already doing so, consider running the Exchange tools created to help you analyze and troubleshoot your Exchange environment. These tools can help make sure that your configuration aligns with Microsoft best practices. They can also help you identify and resolve performance issues, improve mail flow, and better manage disaster recovery scenarios. To run these tools, go to the Toolbox node of the Exchange Management Console. To learn more about these tools, see Managing Tools in the Toolbox.