NS Record Core DNS

The NS record (Name Server record) specifies which DNS servers are authoritative for a domain. NS records are fundamental to how DNS works — they delegate control of a domain (or subdomain) to specific nameservers that hold the actual DNS records.

What Is an NS Record?

An NS record tells the DNS system which servers to query for information about a domain. When you register a domain and set nameservers, you're essentially creating NS records that say "for questions about example.com, ask these servers."

Every domain must have at least two NS records pointing to different nameservers for redundancy. If one nameserver is unavailable, the others can still respond to queries.

NS Record Format

An NS record consists of these components:

example.com.    86400    IN    NS    ns1.example.com.
example.com.    86400    IN    NS    ns2.example.com.

How NS Records Work

When a DNS resolver needs to find information about a domain, it follows the NS record chain:

1. Root servers — The resolver asks root servers about .com
2. TLD servers — Root servers return NS records for .com TLD servers
3. Domain nameservers — TLD servers return NS records for example.com
4. Final answer — The domain's nameservers return the requested record

This hierarchical delegation is what makes DNS scalable — no single server needs to know everything.

Types of NS Records

1. Domain NS Records (at TLD)

These records are stored at your domain registrar and point to your DNS provider:

example.com.    86400    IN    NS    ns1.cloudflare.com.
example.com.    86400    IN    NS    ns2.cloudflare.com.

2. Zone NS Records

These records exist within your DNS zone and should match the registrar NS records:

@    86400    IN    NS    ns1.cloudflare.com.
@    86400    IN    NS    ns2.cloudflare.com.

3. Subdomain Delegation

NS records can delegate a subdomain to different nameservers:

sub.example.com.    86400    IN    NS    ns1.subdomainhost.com.
sub.example.com.    86400    IN    NS    ns2.subdomainhost.com.

Common DNS Providers

Popular DNS providers and their typical nameserver patterns:

Glue Records

When your nameservers are within your own domain, you need "glue records" — A records stored at the parent zone to avoid a chicken-and-egg problem:

; NS records at .com TLD
example.com.        86400    IN    NS    ns1.example.com.
example.com.        86400    IN    NS    ns2.example.com.

; Glue records (A records stored at .com)
ns1.example.com.    86400    IN    A     192.0.2.1
ns2.example.com.    86400    IN    A     192.0.2.2

Without glue records, resolvers couldn't find the IP of ns1.example.com because they'd need to ask ns1.example.com first — a circular dependency.

NS Record Best Practices

• Use at least two nameservers — For redundancy, always have multiple NS records pointing to different servers.
• Geographic distribution — Ideally, nameservers should be in different physical locations.
• Keep registrar and zone NS records in sync — Mismatched NS records can cause DNS issues.
• Use longer TTLs — NS records rarely change, so TTLs of 86400 seconds (24 hours) or more are appropriate.
• Don't use CNAMEs for NS targets — NS records must point to a hostname with A/AAAA records, not CNAMEs.

Changing Nameservers

When migrating to a new DNS provider:

1. Set up all DNS records at the new provider first
2. Lower TTLs on existing records before migration
3. Update NS records at your registrar
4. Wait for propagation (can take 24-48 hours)
5. Verify new nameservers are responding correctly
6. Keep old DNS provider active until propagation completes

NS vs SOA Records

Troubleshooting NS Records

Common issues and solutions:

• Domain not resolving — Check that NS records at the registrar point to active nameservers.
• "SERVFAIL" errors — Nameservers may be misconfigured or unreachable. Test each NS directly.
• Slow resolution after NS change — DNS caching based on old TTL. Wait for propagation.
• Inconsistent responses — Ensure all nameservers have the same zone data.
• Lame delegation — NS record points to a server that doesn't answer for the domain. Fix the NS or server config.