3.1.4.10 Client Domain Controller Location
The client MUST attempt to locate a domain controller of a given domain. A client locally invokes processing rules specified in DsrGetDcName (section 3.5.4.3.3) with the method parameters set as follows:
Set the ComputerName parameter to NULL.
Set the DomainName parameter to the domain name.
Set the DomainGuid parameter to NULL.
Set the SiteGuid parameter to NULL.
Set the Flags parameter to a bitwise OR of the bits L and R that are specified in DsrGetDcNameEx2 (section 3.5.4.3.1).
If DsrGetDcName returns with no errors, the DomainControllerName field of the returned DomainControllerInfo structure will contain the DC name.