Topic Last Modified: 2005-11-17

The Microsoft® Exchange Server Analyzer Tool queries the Active Directory® directory service to determine the value of the fSMORoleOwner attribute of the schema operations master in the Schema Naming Context. For example, in a domain called, fSMORoleOwner for the schema operations master is an attribute of CN=Schema,CN=System,DC=contoso,DC=com. The Exchange Server Analyzer then tries to open a Lightweight Directory Access Protocol (LDAP) connection to TCP port 389 on the domain controller that currently holds this role. If the Exchange Server Analyzer cannot connect to this domain controller, an error is displayed.

The domain controller that holds the schema master role is the only domain controller that can perform write operations to the directory schema. Those schema updates are replicated from the schema master to all other domain controllers in the forest. The schema master is a per-forest operations master role, because regardless of the number of domains, there is only one schema in the forest. To update the schema of a forest, you must have access to the schema master. There can be only one schema master in the whole forest.

To correct this error

  1. Verify that the directory server specified in the error is online and accessible by Exchange servers in your organization.

  2. If this directory server has been decommissioned, you must assign the schema master role to another domain controller.

For more information about transferring the schema operations master role from one domain controller to another domain controller see the following Microsoft Knowledge Base articles: