AZ-400 Practice Exam

To delegate a subdomain like research.adatum.com to a different DNS server, it is necessary to create a Name Server (NS) record in the parent zone, which is adatum.com in this case. The NS record is specifically designed to specify which DNS server is authoritative for a particular subdomain.

When you create an NS record for research in the adatum.com zone, you are indicating that a different DNS server will handle queries for any resource records associated with research.adatum.com. This delegation allows users and systems to query the appropriate DNS server when attempting to resolve domain names or look up resources within that subdomain.

The other record types mentioned serve different purposes. The PTR record is used for reverse DNS lookups, which map IP addresses to domain names and is not applicable for delegating a subdomain. An A record is used to map a hostname to an IPv4 address, but it does not facilitate the delegation of authority for a subdomain. Modifying the Start of Authority (SOA) record is related to how the zone itself operates, including settings for refresh rates and the primary DNS server, but it does not impact DNS delegation for a subdomain.

Thus, the creation of the NS record for the subdomain establishes