This policy setting specifies whether the computers to which this setting is applied attempt DNS name resolution of a single-label domain names.By default the behavior specified in the AllowDnsSuffixSearch is used. If the AllowDnsSuffixSearch policy is disabled then NetBIOS name resolution is used exclusively to locate a domain controller hosting an Active Directory domain specified with a single-label name.If you enable this policy setting computers to which this policy is applied will attempt to locate a domain controller hosting an Active Directory domain specified with a single-label name using DNS name resolution.If you disable this policy setting computers to which this setting is applied will use the AllowDnsSuffixSearch policy if it is not disabled or perform NetBIOS name resolution otherwise to attempt to locate a domain controller that hosts an Active Directory domain specified with a single-label name. the computers will not the DNS name resolution in this case unless the computer is searching for a domain with a single label DNS name that exists in the Active Directory forest to which this computer is joined.If you do not configure this policy setting it is not applied to any computers and computers use their local configuration.
System\Net Logon\DC Locator DNS Records
Machine
At least Windows Server 2003 operating systems or Windows XP Professional
HKLM\Software\Policies\Microsoft\Netlogon\Parameters!AllowSingleLabelDnsDomain
NetLogon.admx