A domain controller provides DNS for a domain. A domain controller stores the zones and records for the domain, and provides DNS services for the domain. When a client computer tries to resolve a name in the domain, the client computer contacts the domain controller for the answer. The domain controller then queries one or more DNS servers for the answer.
If the client computer is connected to the Internet, the DNS server for the domain may be provided by a DNS provider, such as Google. If the client computer is not connected to the Internet, the domain controller may provide the DNS server for the domain.