If your domain is setup as a Single Label Domain or with a Disjoint/Discontiguous namespace, head on over to the DNS Namespace Planning Solution Center.
This Solution Center outlines Microsoft’s support policy for customers with various namespace configurations and includes links to individual products and known technical issues, if any, related to Single Label Domains (SLDs), Disjoint Namespaces, and other uncommon naming configurations.
This Solution Center also provides information on the use of namespace in Microsoft server products, including deployments with Single Label Domains (SLDs), Disjoint Namespaces, and Discontiguous Namespaces.
Single Label Domains Single-label DNS names are DNS names that do not contain a suffix such as .com, .corp, .net, or .org. For example contoso would be an SLD while contoso.com, contoso.net, or contoso.local would not be an SLD.
Disjoint Namespaces A disjoint namespace occurs when one or more domain member computers have a primary Domain Name Service (DNS) suffix that does not match the DNS name of the Active Directory domain of which the computers are members. For example, a member computer that uses a primary DNS suffix of corp.fabrikam.com in an Active Directory domain named na.corp.fabrikam.com is using a disjoint namespace.
Discontiguous Namespaces Discontiguous namespace, also referred to as non-contiguous namespace, is one in which the domains in a forest are not lined up in one hierarchical DNS tree. If the domains in a forest have discontiguous DNS names, they form separate domain trees within the forest. An Active Directory forest can have one or more domain trees. An example of a multi-tree forest would be a forest containing the domains, contoso.com and fabrikam.net.