NS-резолвер
Смотрите, какие name-сервера авторитетны для домена — чтобы поймать ошибки делегирования у регистратора.
AK
appkiro.comCheck the authoritative name servers for a domain and verify DNS delegation.
NS Lookup is for the moment when you are editing DNS in one place but the internet seems to be reading it from somewhere else. It shows which name servers are currently authoritative for the domain.
If the NS records point to the wrong provider, changes in your DNS dashboard may have no public effect. That is why NS is worth checking before debugging A, MX, TXT, or CNAME records one by one.
Run the lookup, then compare the returned name servers with the ones set at your domain registrar. They should match the DNS host you actually intend to use.
Delegation changes are not always instant. It is normal to see old name servers for a while during propagation. Keep the old zone intact until the new delegation is clearly live.
CLI equivalent
dig example.com NSNetwork checks run from the app server, so results reflect what is reachable from that public environment. Localhost, private IPs, and internal-only targets are blocked.
NS records identify the name servers that are authoritative for a domain. Those servers answer DNS queries for the zone.
One common reason is that the domain is delegated to a different DNS provider than the one you are editing.
Most subdomains inherit the parent zone. Separate NS records are only needed when you intentionally delegate a subdomain to another DNS zone.
It depends on TTLs and resolver cache. Some resolvers update quickly, while others may keep the old delegation for hours.