Topic Last Modified: 2005-11-17

The Microsoft® Exchange Server Analyzer Tool queries the Active Directory® directory service to determine whether the ms-DS-ReplicationEpoch attribute of the NTDS Settings object for any domain controller has been set.

An epoch is the time period during which a domain has a specific name. A new epoch starts when a domain is first created, and when a domain name changes.

The ms-DS-ReplicationEpoch attribute is applied to the epoch under which all domain controllers are replicating. If the Exchange Server Analyzer finds that a value has been set for this attribute, a non-default configuration message is displayed.

The presence of a value for the ms-DS-ReplicationEpoch attribute typically indicates that the domain in which the affected server resides was renamed. Microsoft Windows Server™ 2003, Standard Edition, Windows Server 2003, Enterprise Edition, and Windows Server 2003, Datacenter Edition enable administrators to rename domains in an Active Directory forest after the forest structure is in place. The Windows® 2000 Server operating system does not enable administrators to rename domains in an Active Directory forest after the forest structure is in place.

The structure of an Active Directory forest is determined by the order in which you create domains and the hierarchical names of those domains. You start with the forest root domain. All child domains derive their distinguished names and default DNS names from the forest root domain name. You continue in the same way for every additional tree in the forest.

You change the hierarchical structure of an existing domain tree by renaming the domains. For example, you can rename a child domain to have a different parent, or you can rename a child domain to be a new tree-root domain. In both examples, you reposition an existing domain to create a different domain-tree structure.

Also, you can rename domains without affecting the structure. For example, if you rename a root domain, you change the names of all child domains below that root domain. However, you have not created a different domain-tree structure.

Domain renaming is not supported in forests that contain Exchange 2000 Server or Exchange Server 5.5. The Windows Server 2003 domain rename tools were designed for renaming domains in Active Directory forests that do not contain Exchange 2000 Server servers or Exchange Server 5.5 servers. The Windows Server 2003 domain rename tools have this limitation because of the following conditions:

Domain renaming is supported in forests that contain Exchange Server 2003. The Exchange Domain Rename Fix-Up tool (XDR-fixup.exe) fixes Exchange Server attributes after you rename a domain that contains Exchange 2003 Server servers. You can use the Exchange Domain Rename Fix-Up tool with the Windows Server 2003 directory rename tool (Rendom.exe).

For more information about the Windows Server 2003 Active Directory domain rename tools and to download the Windows Server 2003 Active Directory domain rename tools, see "Windows Server 2003 Active Directory Domain Rename Tools" (http://go.microsoft.com/fwlink/?LinkId=40992).

To rename a domain, you must run the XDR-fixup tool. The XDR-fixup tool modifies Active Directory attributes in Exchange Server to reflect the new domain name. The XDR-fixup tool does not replace the Windows Server 2003 domain rename tools. The XDR-fixup tool also does not extend the functionality of the Windows Server 2003 domain rename tools. You must run the XDR-fixup tool every time that you run Rendom.exe.

For more information about the process for renaming domains and how the process for renaming domains affects Exchange Server, see the following tools and documents: