Topic Last Modified: 2008-03-19

The Microsoft Exchange Server Analyzer Tool queries the Active Directory directory service to determine whether DomainPrep was run in the given domain. The version number of DomainPrep acts as the Exchange signature for the domain. The Exchange Analyzer examines the objectVersion attribute of the given domain's Exchange System Objects object. There are two valid integers:

Additionally, the Exchange Analyzer queries the Active Directory directory service to determine the value of the dnsRoot attribute. The value of the dnsRoot attribute represents the uppermost DNS domain name assigned to a domain/directory partition. This is set on a crossRef object and is used, among other things, for referral generation. When searching through an entire domain tree, the search must be initiated at the DNS-Root object.

If the Exchange Analyzer finds the following conditions exist, the Exchange Analyzer displays a warning:

Single-label DNS domain names are DNS names that do not contain a suffix such as .com, .corp, .net, or .org. An example of a single-label DNS domain name would be "Contoso" as opposed to a Fully Qualified Domain Name (FQDN) such as "Contoso.com" or "Contoso.local".

Active Directory domains with single-label DNS domain names will not be supported as a deployment environment for versions of Exchange Server later than Exchange 2007.

To address this warning, it is strongly recommended that you migrate your organization's Exchange environment to a DNS domain that has an FQDN.

Note:
Because Exchange 2007 has already been installed into the organization containing Exchange 2003, or the Exchange 2007 /prepare setup switches have been applied in the domain, you cannot perform a domain rename even if Exchange 2007 servers are removed from the organization. This is because Exchange 2007 setup creates new Active Directory objects which will not be properly renamed by the Exchange 2003 domain rename fixup script. For more information about this issue, see Microsoft Knowledge Base article 300684, "Information about configuring Windows for domains with single-label DNS names" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=300684).

To migrate Exchange 2007 into a fully supported configuration, there are two options:

To migrate Exchange 2007 into a fully supported configuration
  1. If needed, create a new domain with an FQDN.

  2. Use the Active Directory Migration Tool v3.0 (ADMT v3.0) to migrate users, computers, and security groups from your single-label DNS domain to a new domain with a fully-qualified domain name in the same Active Directory forest, or migrate users, computers, and security groups from your single-label DNS domain to a new domain with an FQDN in a different Active Directory forest.

  3. Install Exchange 2007 into the new domain.

    Note   For detailed information about how to migrate individual server roles to the new domain, see the "Procedures for Individual Server Role Migration" section of the topic "Migrating Exchange 2007 on Windows Server 2003 to Exchange 2007 SP1 on Windows Server 2008" (http://go.microsoft.com/fwlink/?LinkId=112028).

  4. Move the user mailboxes following the guidance in the Exchange Server 2007 product documentation topic, "Moving Mailboxes" (http://go.microsoft.com/fwlink/?LinkId=85754).

Note:
In some environments, using database portability instead of the Move Mailbox process may reduce the downtime experienced by users. For example, if the storage that contains the databases can be disconnected from the original server and reconnected to the new server, then database portability would likely be much quicker and result in less downtime than a Move Mailbox operation.

For more information about known issues with Exchange Server 2007 Service Pack 1 (SP1) and single-label DNS domain names, see the Exchange Team blog post, "Single-label Domain Names and Exchange Server 2007 SP1" (http://go.microsoft.com/fwlink/?LinkId=113961).

For information on creating a new domain for Windows Server 2003, see "Deploying Additional Domain Controllers in a New Regional Domain" (http://go.microsoft.com/fwlink/?LinkId=113981).

For information about moving users, computers, and security groups across Active Directory domains or forests, see the following Active Directory resources:

For information about migrating your Exchange 2007 environment to another domain, see "Migrating Exchange 2007 on Windows Server 2003 to Exchange 2007 SP1 on Windows Server 2008" (http://go.microsoft.com/fwlink/?LinkId=112028).