What is an NS record?
An NS (name server) record names a server that is authoritative for a domain — one that holds its DNS zone and answers questions about it. The registry publishes the NS records you set at your registrar, and resolvers worldwide follow them to find every other record of the domain.
What this name server check does
- Looks up the NS records for the name; for a subdomain without its own, it uses the zone of the registrable domain.
- Resolves each name server to its IPv4 and IPv6 addresses.
- Sends each name server a direct query for the zone's SOA record and notes whether it answers, how fast, and which serial number it returns.
- Compares the serials: if they differ, some servers have an older copy of your zone.
Only public addresses are queried. A name server that resolves to a private or reserved address is shown but never contacted. Queries go over IPv4; a server reachable only over IPv6 is listed without a response time.
Reading the results
| Finding | What it means | Fix |
|---|---|---|
| All answer, same serial | Healthy delegation | Nothing to do |
| Only one name server | A single point of failure | Add a second, ideally on another network |
| Name server did not answer | Lame delegation: listed, but not serving the zone | Add the zone on that server, or remove it at the registrar |
| Serials differ | Zone transfers are failing or slow | Check NOTIFY / AXFR between primary and secondaries |
| Name server has no address | Its hostname does not resolve | Fix the name or its glue records at the registrar |
| All on one /24 | One network outage takes DNS down | Use servers on separate networks or providers |
How to change name servers
Name servers are set at your registrar, not in the DNS zone itself. When moving DNS to a new provider, copy every record into the new zone first, then change the name servers at the registrar, and keep the old zone running for two days — the NS records in the top-level domain's zone are cached for up to 48 hours.
Find your registrar with the WHOIS lookup, and follow the switch from resolvers worldwide with the DNS propagation checker (record type NS).
$ dig example.com NS +short
$ dig @ns1.example-dns.net example.com SOA +short
$ nslookup -type=NS example.comWhy two or more name servers
RFC 1034 asks for at least two name servers, and most registries enforce it. If your only name server is down, every record — website, email, certificate validation — stops resolving once caches expire. Two servers on the same machine or the same network do not help much; spread them across providers or use a provider with anycast.
- Secondary DNS from a second provider protects against a provider-wide outage; both must serve identical zones.
- Keep TTLs on NS and SOA records sensible (hours, not minutes) so resolvers can ride out a short outage.
- Watch for unintended changes: NetworkAI's monitor checks DNS and registration daily and alerts you when something breaks.
To see all of a domain's records — not just NS — use the DNS lookup, or run the domain health check for DNS, certificates, email authentication and expiry in one report.