This Computer Belongs to a Single-Labeled DNS Domain

[This topic is intended to address a specific issue called out by the Exchange Server Analyzer Tool. You should apply it only to systems that have had the Exchange Server Analyzer Tool run against them and are experiencing that specific issue. The Exchange Server Analyzer Tool, available as a free download, remotely collects configuration data from each server in the topology and automatically analyzes the data. The resulting report details important configuration issues, potential problems, and nondefault product settings. By following these recommendations, you can achieve better performance, scalability, reliability, and uptime. For more information about the tool or to download the latest versions, see "Microsoft Exchange Analyzers" at]  

Topic Last Modified: 2008-11-03

Microsoft Exchange Server 2007 setup is issuing a warning because the local computer belongs to a single-labeled DNS domain.

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 Server 2007.

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 "" or "Contoso.local".

To address this warning, it is strongly recommended that you change your organization's DNS domain name to an FQDN.

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


The content of each blog and its URL are subject to change without notice.

For information about how to rename your domain, see the following Windows Operating System and Active Directory resources: