Find the name servers a domain is delegated to, and how long resolvers cache them
Runs in your browser. Only the lookup you start is sent to cloudflare-dns.com or dns.google; nothing else leaves your device. Updated on 25 Oct 2026.The NS records say which servers hold the authoritative copy of a zone, which is how you check that a move to a new DNS host has taken effect. Type the domain to see its name servers as a public resolver has them, each with the TTL it will be cached for. If the old provider still shows, that cached copy has not expired yet, or the registrar has not been updated.
Keep NS selected in the Record type list; the page opens on it.
Type the domain, such as example.com, and press Look up.
Read the name servers in the Data column and the TTL each one is cached for.
Switch Resolver to the other one to see whether both caches already show the new name servers.
This DNS lookup asks a public resolver, Cloudflare 1.1.1.1 or Google 8.8.8.8, the same question dig or nslookup would, and shows the answer in a table. Pick one record type, or "All common types" to ask for A, AAAA, CNAME, MX, NS, TXT, SOA, CAA and HTTPS together. Every record shows its TTL in seconds and in words, because the TTL is how long any copy of it may be cached.
A browser cannot send DNS packets itself, so the page uses DNS over HTTPS. The name you type goes to the resolver you chose, which is how it gets an answer; nothing else about you or your other searches is sent. You see what that resolver has in its cache, which can lag a recent change by up to the record's TTL. To compare two resolvers side by side, use the DNS Propagation Checker.
The tool does not do zone transfers, query a domain's own name servers directly, or show records at names you do not type: DNS has no way to list every subdomain.
The rest of the article, and all 6 questions about DNS Lookup, are on the DNS Lookup page.
A resolver that already cached the old answer keeps it until its TTL runs out, then asks again. A name that did not exist is remembered as missing for the SOA record's last number of seconds. Wait that long, or compare both resolvers in the DNS Propagation Checker.
NXDOMAIN is the DNS answer for a name that does not exist at all, for any record type. Common causes are a typo, a subdomain that was never created, or a domain that has expired. A name that exists but lacks the type asked for gets a different answer: no records.
SERVFAIL means the resolver tried and could not get a trustworthy answer. Either the domain's own name servers did not reply, or the answer failed DNSSEC validation. The DNS Propagation Checker asks again with DNSSEC checking off, which shows which of the two it is.
No. DNS answers questions about names you already know; there is no query that lists every name in a zone, and zone transfers are refused by almost every public server. Certificate transparency logs are the usual way to discover subdomains, and this tool does not search them.
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Same job, other tools: AS Number Lookup – Turn an AS number into the network name, registry and allocation date · IP to ASN Lookup – Map an IP address to the ASN that announces it, with the BGP prefix.
On the related tools: Open Port Checker – See if a port forwarded on your router is reachable from the internet.