Glossary

NS Record

Identifies the authoritative name servers for a domain

An NS record (Name Server record) specifies the authoritative DNS name servers for a domain, telling the global DNS system which servers hold the official DNS records for that domain.

What is an NS Record?

An NS record, short for Name Server record, is a fundamental DNS record type that identifies which DNS servers are authoritative for a given domain. These are the servers that hold the official, definitive DNS records for that domain — including its A records, MX records, TXT records, and all others. Every domain must have at least two NS records for redundancy.

When you register a domain, your registrar asks you to specify name servers. The registrar then publishes your NS records in the parent TLD zone (for example, in the .com zone for a .com domain). This is what connects the global DNS hierarchy to your specific domain: when a resolver asks the .com name servers about your domain, they respond with your NS records, directing the resolver to your authoritative servers.

NS records are typically controlled by your DNS hosting provider, which may be your domain registrar, a dedicated DNS service like Cloudflare or Route 53, or your web host. Changing NS records is how you delegate DNS management from one provider to another.

How Does an NS Record Work?

NS records are central to the hierarchical delegation model of DNS. The global DNS tree starts at the root, which delegates to TLD servers (.com, .net, .org, etc.), which in turn delegate to the authoritative name servers for individual domains via NS records.

When a resolver needs to look up example.com, it first queries the root servers, which respond with the .com TLD servers. The .com servers respond with the NS records for example.com — for instance, ns1.exampledns.com and ns2.exampledns.com. The resolver then queries those name servers directly and receives the actual DNS records (A, MX, TXT, etc.) for the domain.

The NS records published at the TLD level are called delegation NS records. Your authoritative name servers also publish their own copy of the NS records inside your zone file; these are called authoritative NS records. Both sets should match — discrepancies between them (called lame delegations) can cause DNS resolution failures and are a common misconfiguration to check for during troubleshooting.

How to Check an NS Record

You can look up the name servers for any domain using the NS Lookup tool at nslookup.net/tools/ns-lookup. Entering a domain returns its current NS records as seen from multiple vantage points on the internet. This is essential when migrating DNS providers, troubleshooting lame delegations, or verifying that a recent NS change has propagated through the global DNS infrastructure.

Related Tool

NS Lookup

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Frequently Asked Questions

How many NS records does a domain need?

A domain must have a minimum of two NS records, one primary and one secondary, for redundancy. If one name server is unreachable, the other can still respond to DNS queries. Many enterprise domains use three or more name servers spread across different geographic locations and networks for additional reliability.

What happens if I change my NS records?

Changing NS records initiates a transfer of DNS authority from one provider to another. Once the new NS records propagate (which typically takes up to 48 hours, though often much faster), DNS resolvers worldwide will start querying your new name servers for all records. It is critical to set up all DNS records on the new provider before changing NS records to avoid downtime.

Can I use different NS records for a subdomain?

Yes. You can delegate a subdomain to a completely different set of name servers by adding NS records for that subdomain in your zone file. This is called subdomain delegation and is commonly used in large organizations where different teams manage different parts of the domain namespace independently.

What is a lame delegation?

A lame delegation occurs when the NS records for a domain point to name servers that are not configured to be authoritative for that domain. This means the name servers exist and respond but return errors or empty answers instead of the domain's records. Lame delegations cause intermittent DNS resolution failures and must be corrected at both the registrar and the DNS host.