Which DNS resource record type identifies the primary DNS server for a DNS zone?

The type of DNS resource record that identifies the primary DNS server for a DNS zone is the SOA record, which stands for Start of Authority. This record contains essential information regarding the zone, including the primary authoritative nameserver, the contact email for the administrator, and various timers related to refreshing, retrying, and expiring the record data.

Specifically, the SOA record indicates which server is the master for that domain, meaning it is responsible for maintaining the authoritative information about that domain's records. Other DNS servers may query this primary server to obtain the zone data for the domain, which helps ensure that requests to your domain are handled by an authoritative source. This foundational structure is crucial for the functioning of the DNS system, providing a clear point of reference for the management and retrieval of domain-related information.