NS Lookup
See which nameservers are authoritative for a domain.
NS records record a delegation: they name the servers that hold the authoritative answers for a zone. When a resolver looks up anything under a domain, it works down from the root, follows NS records at each level, and eventually asks one of the nameservers listed here. Those servers are the source of truth for every other record in the domain.
This makes NS records the first thing to check when DNS behaves inconsistently. Two lookups returning different answers usually means the delegation points at two sets of nameservers holding different zone data — the classic symptom of a provider migration that changed the zone but not the delegation, or the other way round.
The records live in two places, which is a common trap. The parent zone holds the delegation your registrar publishes, and your own zone holds an NS record set of its own. When those disagree, resolvers may use either, and the resulting intermittent failures are hard to reproduce. After changing DNS providers, confirm both agree.
What this tool does
The authoritative set
These are the nameservers the rest of the internet will ask about this domain. Everything else in its DNS comes from them.
Verify a DNS migration
Changing DNS provider means changing these records at the registrar. Until they update, your new zone is not being used at all.
Spot a split delegation
Nameservers from two different providers usually means a half-finished migration, with answers depending on which server a resolver happens to ask.
Check redundancy
Two nameservers is the practical minimum, and having them on separate infrastructure is what protects a domain from a single provider outage.
Frequently asked questions
What is an NS record?
An NS ("nameserver") record names a server that is authoritative for a DNS zone — one that holds the real records for the domain rather than a cached copy. Resolvers follow NS records down from the root to find which servers to ask about a given name.
How do I change my nameservers?
At your registrar, not in your DNS zone. The delegation lives in the parent zone, which only the registrar can update, so pointing a domain at a new DNS provider means editing the nameserver list in the registrar's control panel. Changes can take up to 48 hours to be seen everywhere.
How many nameservers should a domain have?
At least two, and ideally on independent infrastructure. Two is the practical minimum for redundancy, most registrars require it, and having them in different networks or regions is what keeps a domain resolving through a single provider's outage.
Why do different tools show different nameservers for my domain?
Usually because a change is still propagating: some resolvers hold the old delegation until it expires from cache. If it persists, the parent delegation and the NS records inside your own zone probably disagree, which leaves resolvers free to use either set.
What is the difference between NS records and glue records?
NS records name your nameservers; glue records supply their IP addresses in the parent zone. Glue matters when the nameservers are inside the domain they serve — ns1.example.com being authoritative for example.com would be circular, so the parent publishes the address directly to break the loop.
What happens if my NS records are wrong?
The domain stops resolving entirely, once caches expire. Nothing under it works — no website, no email, no subdomains — because there is no way to reach the records. It is the single most disruptive DNS mistake, which is why nameserver changes deserve checking twice.
Monitor it, don't just check it
One-off checks catch what is broken today. CertNotify watches your certificates, domains, DNS and code continuously and tells you before something breaks.