What does NS lookup actually tell me?

Which nameservers are authoritative for the domain, that is, the machines that hold the live DNS zone. Useful for: confirming who is hosting your DNS (Cloudflare, Route 53, GoDaddy), debugging a recent NS change, or spotting that a domain is accidentally delegated to two providers at once.

I just changed nameservers but NS lookup still shows the old ones. Why?

Two layers of caching. The NS records at the registry (TLD) propagate within a few hours, but caches all the way down the resolution chain (yours, the packet.guru server's, your ISP's) may hold the old NS for hours to days. The tool bypasses your local cache, but the packet.guru server's resolver may still hold the old answer until its TTL expires. Give a registrar-level NS change 24 to 48 hours before declaring it broken.

The NS line shows servers from two different providers. Is that a problem?

Usually yes. If you migrated DNS from Provider A to Provider B but never removed A from the registrar settings, the registry will keep listing both. Roughly half your queries hit A (stale records) and half hit B (current), so users get inconsistent answers. Fix: remove the old NS at the registrar.

Does NS lookup work for subdomains?

Only if the subdomain has its own zone delegation (its own NS records at the parent zone). Most subdomains share the apex zone and will return no NS records of their own. If unsure, try the apex domain instead.

Where does the data come from?

The NS query runs from the packet.guru server, not from your browser. The answer bypasses your browser and OS cache. It still respects the record's TTL on the server side.

Free, no signup, rate-limited per IP.

DNS

NS Lookup

Name server records

Input

Identify the Authoritative Name Servers for a domain. These are the servers that hold the "truth" about your DNS records.

Terminal

Console ready. Execute a command to see output...

About NS Lookup

Who holds the keys?

NS (Name Server) records define which servers are authoritative for a domain. If you change hosting, you usually update these to point to the new provider.

Debugging

If you updated DNS records but don't see them, check your NS records to ensure you are updating the right nameservers (e.g., did you leave Cloudflare on but edited GoDaddy?).

How to use NS Lookup

Enter the apex domain
example.com. No subdomain unless you know that subdomain has its own NS delegation.
Hit Lookup
Each line is a nameserver hostname.
Cross-check with the registrar
Compare with what your registrar's NS settings show. Same names on both sides means the delegation is healthy. A mismatch means the registrar and DNS provider are out of sync. After changing nameservers, use the DNS Propagation Checker to watch the NS change spread worldwide.
Verify the records served
Use DNS Lookup on a specific record type (A, MX) to confirm the NS is actually serving the right zone. Use Whois to see what NS the registrar reports for the domain.

Frequently Asked Questions

: Which nameservers are authoritative for the domain, that is, the machines that hold the live DNS zone. Useful for: confirming who is hosting your DNS (Cloudflare, Route 53, GoDaddy), debugging a recent NS change, or spotting that a domain is accidentally delegated to two providers at once.
: Two layers of caching. The NS records at the registry (TLD) propagate within a few hours, but caches all the way down the resolution chain (yours, the packet.guru server's, your ISP's) may hold the old NS for hours to days. The tool bypasses your local cache, but the packet.guru server's resolver may still hold the old answer until its TTL expires. Give a registrar-level NS change 24 to 48 hours before declaring it broken.
: Usually yes. If you migrated DNS from Provider A to Provider B but never removed A from the registrar settings, the registry will keep listing both. Roughly half your queries hit A (stale records) and half hit B (current), so users get inconsistent answers. Fix: remove the old NS at the registrar.
: Only if the subdomain has its own zone delegation (its own NS records at the parent zone). Most subdomains share the apex zone and will return no NS records of their own. If unsure, try the apex domain instead.
: The NS query runs from the packet.guru server, not from your browser. The answer bypasses your browser and OS cache. It still respects the record's TTL on the server side.
: Free, no signup, rate-limited per IP.