NS record

An NS record (Name Server) is a DNS entry that names the authoritative name servers for a given domain — the ones that officially hold its zone with all the other records (A, MX, TXT and so on). An NS record performs delegation: it tells the rest of the internet whom to ask about entries for this domain.

What an NS record involves

Delegation works on two levels. The top-level domain registry (e.g. .com) holds NS records pointing to the domain's name servers; those in turn contain identical NS records inside their own zone. A typical setup uses at least two servers, e.g. ns1.provider.com and ns2.provider.com, for redundancy. When a name server sits under the same domain as the delegated zone, you also need glue records — IP addresses entered directly in the registry to break the loop.

The NS record in practice

You change NS records when moving a domain's DNS hosting to a new provider — for example from the registrar's panel to an external DNS platform or a CDN. Changing name servers is one of the most fundamental domain operations: once done, the whole propagation of the new zone depends on the delegation TTL at the TLD level, which can be measured in hours. That is why DNS migrations are planned with a margin, keeping parallel, consistent zones at both providers for a while.