మాడ్యూల్ పాఠాలు (3/4)
NS e glue record
NS and glue records
NS records name the servers for a zone. Sometimes the name server is inside the zone it serves. That creates a circular dependency: to ask ns1.example.test for an address, the resolver first needs the address of ns1.example.test.
Why glue breaks the loop
The parent can include an address for an in-zone name server as glue. It gives the resolver a way to make the first contact; the child’s own authoritative A or AAAA record remains the source of truth. Glue is supporting data, not a replacement for the child’s address record.
If the name server is outside the child—for example, ns1.provider.test—its address can be resolved through the provider’s own delegation, so the same circular dependency does not arise. Stale glue can still send resolvers to the wrong address and must be updated with the delegation.
Trace root → TLD → delegated zone. At each step, note the server queried, the referral received, and which part of the name that server can answer.
Check your understanding
Choose the best answer. This quiz runs locally and sends no DNS queries to real domains.
Why can `ns1.example.test` need glue?