Nameserver Checker
Identify the authoritative nameservers for a domain and confirm delegation.
What this tool does
This tool shows the authoritative nameservers (NS records) that control DNS for a domain. It helps you verify delegation settings after registrar or hosting changes. The results indicate where DNS records are hosted and which provider is responsible for answering authoritative queries.
Inputs explained
- Domain name: The root domain you want to inspect, such as example.com.
How it works / Method
The tool performs a DNS query for NS records and displays the nameservers returned by public resolvers. These results reflect delegation data and may be cached based on TTL. The lookup is read-only and does not change any DNS settings.
Nameservers Found:
Example
Input: Domain: example.com. Expected output: A list of authoritative nameservers such as ns1.example.net and ns2.example.net. If delegation recently changed, you may see old nameservers until caches expire.
Use cases
- Confirm a registrar nameserver update after migrating DNS providers.
- Verify delegation before troubleshooting DNS record issues.
- Audit which vendor controls a domain's authoritative DNS.
- Detect misconfigurations that can cause site or email outages.
- Review nameserver setup during acquisitions or security checks.
Limitations & notes
- Results can be delayed by resolver caching and parent zone TTL values.
- Glue record issues can cause inconsistent nameserver visibility.
- The tool reads public DNS and cannot see private or internal zones.
- Temporary resolver errors may appear even if delegation is correct.
Accuracy & Disclaimer
Nameserver results are based on public resolver responses at query time. Confirm critical changes with your registrar or DNS provider.
Frequently Asked Questions
What are authoritative nameservers?
Authoritative nameservers are the DNS servers that host the zone data for a domain and provide the final answer to queries about that domain. They contain the official records for A, MX, TXT, and other types. Recursive resolvers rely on these servers to obtain the source of truth. If the authoritative nameservers are misconfigured, the domain may not resolve correctly even if settings look right at the registrar.
Why do nameservers differ from my registrar settings?
Registrar settings update the delegation at the parent zone, but those changes can take time to propagate. Caches and TTL values at the TLD can delay what resolvers see. If the domain uses in-bailiwick nameservers, glue records also affect results. It is normal to see a short mismatch after changes. If the mismatch persists, confirm the registrar update and check for typos in nameserver hostnames.
What are glue records and when are they needed?
Glue records are IP addresses stored in the parent zone for nameservers that are within the same domain they serve, such as ns1.example.com for example.com. Without glue, resolvers would face a circular dependency when trying to resolve the nameserver. Glue is managed at the registry or registrar level as part of delegation. If glue records are missing or incorrect, resolution can fail even if the zone itself is correct.
What if no nameservers are found?
If no NS records are returned, the domain may not be delegated, may be expired, or may not exist. It can also indicate a DNS configuration issue at the registry or a transient resolver error. Confirm the domain registration status, check RDAP data, and verify that the domain is pointed to active nameservers. After changes, wait for TTLs to expire and try again.
How long do nameserver changes take?
Nameserver changes depend on the parent zone TTL and caching across resolvers. Some updates appear within minutes, but others can take several hours. Unlike individual record edits at the DNS provider, delegation changes must be picked up at the TLD level first. Plan a window of up to 24 to 48 hours for global consistency, and keep old nameservers running during the transition.
Can I check nameservers for a subdomain?
You can check subdomain nameservers only if the subdomain has its own delegated NS records (a zone cut). If it does not, the subdomain inherits the parent domain's nameservers, and the results will look the same as the root domain. For delegated subdomains, the tool will show the NS records set at the delegation point. If you are unsure, start with the root domain and compare.
Sources & references
- RFC 1034: Domain names - concepts and facilities - DNS architecture and delegation concepts.
- RFC 1035: Domain names - implementation and specification - NS record behavior and resolution flow.
- RFC 2308: Negative caching of DNS queries - Explains cached DNS responses and errors.
- IANA Root Zone Management - Authoritative TLD delegation context.