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

A DNS failure occurred at the Send connector. See the associated diagnostic information.


This Warning event indicates a Domain Name System (DNS) failure occurred on the specified Send connector.

When the Send connector is set to use DNS mail exchange (MX) records to route mail automatically, the DNS client on the source server must be able to resolve public DNS records. By default, the DNS server that is configured on the source server's internal network adapter is used for name resolution. You can configure a specific DNS server to use for internal and external DNS lookups by using the Exchange Management Console to modify the DNS settings on the Exchange server properties. You can also use the Exchange Management Shell to configure the parameters in the Set-TransportServer cmdlet.

If you configure a specific DNS server on the transport server to use for external DNS lookups, you must select Use the external DNS lookup settings on the transport server on the Network Settings page of the New SMTP Send Connector wizard or, in the Shell, on the Set-TransportServer cmdlet, set the UseExternalDNSServersEnabled parameter to $True. The DnsRoutingEnabled parameter on the Send connector must also be set to $True.

For more information, see the following topics:

  • Understanding Send Connectors

  • Set-TransportServer

User Action

To resolve this warning, do one ore more of the following:

  • Verify that DNS is configured correctly on the Exchange server and that the configured DNS servers are functional and reachable. You can use the Nslookup tool to test DNS server functionality.

  • Review the Application log for related events. For example, events that occur immediately before and after this event may provide more information about the root cause of this error.

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.