Process %1 (PID=%2). The domain controller %3 is running Windows %4 %5. Exchange Active Directory Provider requires that domain controllers are running Windows Server 2003 Service Pack 1 or later versions of Windows.

This Warning event indicates that the domain controller specified in the event description is running Microsoft® Windows® 2003 Server Service Pack 1 (SP1) or later version of Windows. This event may also occur when one or more of the following conditions are true:

• The Microsoft Exchange Active Directory® Topology service is unable to read the serverName attribute on the RootDSE.

• The Microsoft Exchange Active Directory Topology service is unable to read the serverReference attribute from the Active Directory configuration naming context. For more information about RootDSE attributes, see RootDSE at the MSDN Web site.

• The Lightweight Directory Access Protocol (LDAP) query of the Active Directory domain naming context for theoperatingSystem and operatingSystemServicePack attributes failed. These attributes are missing or corrupted.

You will see Unknown Operating System and Unknown Service Pack in the event description when one or more of the conditions explained here are true.

The domain controller specified in the event description will not be used. As long as there is sufficient capacity in alternative, appropriate domain controllers, mail flow will not be interrupted. However, it is recommended the issue be investigated and fixed as soon as possible.

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

• Upgrade the domain controller specified in the event description to Windows 2003 Server SP1 or later version of Windows.

• If you see Unknown Operating System and Unknown Service Pack in the event description, do one or more of the following:

  • Make sure that the account you are logged in as has Read permissions on the RootDSE.

  • Check network connectivity to the domain controller specified in the event description. For more information, see Microsoft Knowledge Base article 325487, How to troubleshoot network connectivity problems.

• Run the Dcdiag command line tool to test domain controller health. To do this, run dcdiag /s:<Domain Controller Name> at a command prompt on the Exchange Server. Use the output of Dcdiag to discover the root cause of any failures or warnings that it reports. For more information, see Dcdiag Overview at the Microsoft Windows Server TechCenter.

If you are not already doing so, consider running the tools that Microsoft Exchange offers to help administrators analyze and troubleshoot their Exchange environment. These tools can help you make sure that your configuration is in line with Microsoft best practices. They can also help you identify and resolve performance issues, improve mail flow, and better manage disaster recovery scenarios. Go to the Toolbox node of the Exchange Management Console to run these tools now. For more information about these tools, see Toolbox in the Exchange Server 2007 Help.