Azure DNS Delegation Checker
Verify a domain is correctly delegated to Azure DNS: compares the NS records the world sees against the four name servers assigned to your zone, and catches mixed, stale or recreated-zone delegations.
✓ runs in your browser — pasted data never leaves this page; the optional DNS fetch uses our server (disclosed below)
⚠ The lookup sends the zone name from our server to Cloudflare's public resolver —
your browser never contacts a third party, and the name is not stored.
Prefer to keep everything local? Paste the output of dig NS yourdomain.com below instead.
Paste NS records manually instead
Assigned name servers (optional — from the zone's overview page in the Azure portal)
Frequently asked
What does the server-side lookup send?
Only the zone name you type. Our server forwards it to Cloudflare's public resolver and returns the NS records — your browser never contacts a third party, and the name is not stored.
Can I use it without the lookup?
Yes. Run dig NS yourdomain.com (or Resolve-DnsName yourdomain.com -Type NS) yourself and paste the result — then everything runs in your browser.
Why must all four name servers match?
Azure assigns each zone one server in each of azure-dns.com/.net/.org/.info, sharing a numeric suffix. A partial set weakens resolution; a mixed-suffix set usually means the zone was recreated and the registrar still points at the old assignment — the classic 'Azure DNS randomly stopped resolving' cause.