Nameserver Check
Compare the nameservers set at the registry with what the authoritative servers report, and check each server responds correctly.
What this tool checks
- The delegation published by the parent (registry) zone
- NS records reported by each authoritative server
- Reachability and authoritative answers from every nameserver
- SOA serial agreement across servers
- Glue records and registry status
How to read the results
- Pass
- The check succeeded based on the observed responses.
- Warning
- Works now, but is risky, unusual or worth reviewing.
- Fail
- A problem was observed directly in the responses.
- Inconclusive
- Not enough evidence — for example a server did not respond.
Frequently asked questions
- How do I find out which nameservers a domain uses?
- Enter the domain above. The check reads the nameservers published by the registry, which are the ones set at your registrar, and compares them with the NS records each of those servers reports.
- Why are my nameservers not updating?
- Registries usually publish a nameserver change within minutes, but resolvers can keep the old delegation cached for up to 48 hours for .com and .net. If the registry still lists the old servers here, the change has not gone through at your registrar.
- What is a lame nameserver?
- A nameserver listed for a domain that does not actually serve it: it refuses queries, returns errors or answers without authority. It causes slow lookups and intermittent failures, usually after a move to a new DNS provider.
- Should my registrar's nameservers match my NS records?
- Yes. Resolvers find your zone through the registrar's list and may then switch to the zone's own NS records, so when the two lists differ, different users can reach different servers.