Applies to: Exchange Server 2007 SP1, Exchange Server 2007
Topic Last Modified: 2009-05-21

Single-label DNS domain names are DNS names that don't contain a suffix such as .com, .corp, .net, or .org. An example of a single-label DNS domain name is "Contoso" as opposed to a fully qualified domain name (FQDN) such as "" or "Contoso.local". The release to manufacturing (RTM) version of Microsoft Exchange Server 2007 didn't allow the installation of Exchange into a single-label domain. However, in Exchange Server 2007 Service Pack 1 (SP1), you can now install Exchange into single-labeled domains.

To transition Exchange 2007 into a fully supported configuration, you have two options:

To transition Exchange 2007 into a fully supported configuration, perform the following tasks:

  1. Create a new domain with a FQDN. For information about creating a new domain for Windows Server 2003, see Deploying Additional Domain Controllers in a New Regional Domain. For information about installing and upgrading to Windows Server 2008, see Windows Deployment Services Step-by-Step Guide.

  2. Migrate your users, computers, and security groups from your single-label DNS domain to the new domain. Use the Active Directory Migration Tool v3.0 (ADMT v3.0). For more information about the ADMT tool, including a download, see Active Directory Migration Tool v3.0. For documentation, see ADMT v3 Migration Guide.

  3. Install Exchange 2007 into the new domain. For detailed information about how to deploy individual server roles to the new domain, see New Installation or the "Procedures for Individual Server Role Migration" section of Migrating Exchange 2007 on Windows Server 2003 to Exchange 2007 SP1 on Windows Server 2008.

  4. Move your user mailboxes. For more information about moving Exchange mailboxes, see Moving Mailboxes.

For More Information

For more information about Exchange 2007 SP1 and single-label DNS domain names, see the Exchange Team blog post, Single-label Domain Names and Exchange Server 2007 SP1.

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