What is authoritative DNS?

Authoritative versus recursive

Recursive resolvers are what laptops and phones talk to — often the ISP or a public resolver. They cache answers and ask authority when they do not have one.

Cloud DNS is authoritative. It answers for zones you host. It is not a public recursive service for the whole internet.

The delivery model

Why unicast nameservers are a single path

Two nameserver hostnames can still share network or operational dependencies. Anycast can distribute reachability across locations, but provider diversity, zone consistency, and failure handling need their own review.

That is the DNS equivalent of a CDN: the record is the same, the place it is answered from is not.

Records are policy, not just addresses

DNS records describe services and routing policy. A and AAAA publish addresses; additional features may include health-aware answers, geographic routing, and apex aliases. Confirm which features your provider implements.

Registrar DNS is fine for a parked domain. It is a poor control plane for a shop or an API that must move.

Delegation is the cutover

You import the zone, prove records, then change NS at the parent. Mail and verification TXT should be in the imported zone so they do not vanish when NS moves.

Do not mix this up with pointing a single A record at Cloud CDN. That is a record change. Delegation is who is allowed to answer the zone.

Validate before production

Compare the parent delegation with the NS records in the zone. Query every delegated server directly for the same A, AAAA, and MX records. Check DNSSEC validation separately when the zone is signed.

• Record the configuration and expected result before changing traffic.
• Keep evidence of the test and a working rollback for the previous behavior.