Topic Last Modified: 2005-11-18

The Microsoft® Exchange Server Analyzer Tool queries the Win32_Service Microsoft Windows® Management Instrumentation (WMI) class to determine the value of the Started key for the DNS Server service (DNS). A value of True indicates that the DNS Server service is running on this Exchange server.

The Exchange Server Analyzer also queries the Win32_OperatingSystem WMI class to determine the value for the OSProductSuite key. The value returned for this key indicates the version of Windows operating system that is running on the Exchange Server computer.

Additionally, the Exchange Server Analyzer also queries the Active Directory® directory service to determine the count of the entries listed in the homeMDBBL attribute of each mailbox store. The count of this attribute represents the number of mailboxes on the mailbox store.

If the Exchange Server Analyzer determines that the DNS Server service is started on an Exchange Server computer that meets the following criteria, a warning is displayed:

Running DNS Server service on the same computer as a production Exchange mailbox server is not recommended. Co-hosting DNS Server service and Exchange Server on the same computer in a production environment will likely lead to poor performance by one or both of the servers.

To correct this warning

  1. You should consider one of the following options to correct this warning:

    • Move either Exchange Server or DNS Server service off the computer. Completely removing one of the server applications from the computer is recommended.

    • Move the Exchange mailboxes off the server. At a minimum, you should remove the mailboxes and convert the Exchange server to a protocol or infrastructure server. This will reduce the load considerably for disk I/O and marginally for CPU (the latter depends on the Exchange infrastructure role).

    • Consider installing Small Business Server instead. If you are running Exchange in a small environment with less than 75 users where you do not require more than one Exchange server, you may benefit from installing Small Business Server. Small Business Server includes both Microsoft SQL Server™ and Exchange Server, along with other core Microsoft server applications and has been developed, tested, and optimized for a single-computer installation.

For more information about moving mailboxes and Exchange servers, see the following Microsoft Knowledge Base articles:

For more information about Small Business Server, see "Microsoft Windows Small Business Server 2003" (