In the Windows Server DNS planning guidance from Administering Windows Server Hybrid Core Infrastructure , forwarders can be used to centralize name resolution through a designated DNS server. The guide states that a DNS server can be configured to "forward queries it cannot resolve to one or more upstream DNS servers" and that this is often used to "centralize Internet and internal namespace resolution through an authoritative hub server." In this scenario, Server1 hosts the contoso.local parent zone and already contains delegations to east.contoso.local and west.contoso.local. If Server2 and Server3 are set to forward unresolved queries to 10.0.1.10 (Server1), they will resolve:
* Internal names-Server1 is authoritative for the parent and, through delegations, can refer requests to the appropriate child-zone servers.
* Internet names-Server1 uses root hints and can resolve external hosts, with Server2/Server3 receiving the answers via forwarding.
The study materials emphasize: "Delegations enable a parent zone to direct queries to child zones," and
"forwarders do not break authority-authoritative data is answered locally; only unresolved names are forwarded." Thus, configuring Server2 and Server3 to forward to Server1 satisfies the requirement that all DNS servers resolve all internal namespaces and Internet hosts, while keeping the design simple and consistent with DNS best practices.