DNS Propagation Checker

Compare DNS answers from three major public resolvers — Cloudflare, Google, and Quad9 — side by side for the same domain and record type. Spot propagation gaps after DNS changes when one resolver still caches an old A, AAAA, CNAME, MX, NS, or TXT answer while others already show the update. Displays per-resolver latency, TTL, and a Propagated vs Differences detected summary. Helpful during cutovers — not a guarantee of worldwide DNS consistency because many other resolvers exist globally.

How to Use the DNS Propagation Checker

Enter a domain, pick a record type, and compare answers from Cloudflare, Google, and Quad9 to see whether DNS changes have propagated.

  1. Open DNS Propagation Checker.
  2. Enter the domain whose records you recently changed.
  3. Select the record type you updated (A for website IP, MX for mail, TXT for verification, etc.).
  4. Click Compare to query all three resolvers in parallel.
  5. Read the Propagated or Differences detected badge at the top.
  6. Expand each resolver panel — compare Type, TTL, and Data columns side by side.
  7. If differences remain, wait for TTL expiry or verify authoritative DNS at your provider, then compare again.

Why resolver answers diverge

Each resolver caches answers for the TTL returned by authoritative nameservers. After you change DNS, resolvers that queried before the change keep serving stale data until their cache entry expires. Comparing three large public resolvers catches many common propagation delays.

Worked example

  • Website IP change — A record shows old IP on Quad9 but new IP on Cloudflare and Google: wait or flush is not possible on public resolvers; TTL governs update.
  • Email migration — MX priorities match on all three panels: safe to proceed with mail flow testing.
  • TXT verification — new SPF string visible everywhere: proceed with provider domain verification.

Common mistakes

  • Checking immediately after a change without lowering TTL first.
  • Testing the wrong record type — CNAME at CDN vs A at origin during mixed setups.
  • Assuming three green panels mean every user worldwide has updated instantly.

Limitations

Samples three resolvers only — not a exhaustive global anycast map. Does not query authoritative nameservers directly. Use DNS Lookup against each resolver for deeper single-target analysis.

FAQ

How is this different from DNS Lookup?

DNS Lookup queries one resolver at a time. Propagation Checker queries Cloudflare, Google, and Quad9 in parallel and highlights mismatches.

What does Propagated vs Differences detected mean?

Propagated means all three resolvers returned the same answer set for the chosen type. Differences detected means at least one resolver disagrees — often due to TTL caching or incomplete updates.

Which record types can I compare?

A, AAAA, CNAME, MX, NS, and TXT — the types most commonly changed during website and email migrations.

Does green mean the whole world sees my new DNS?

No. Only these three public resolvers are tested. ISPs and corporate resolvers worldwide may still cache old data until TTL expires.

How long does propagation take?

Depends on prior TTL values and resolver caches. With TTL 300 (5 minutes), many resolvers update within minutes; old TTLs of 86400 can take up to 24 hours.

Why does one resolver show Failed?

Transient network errors, resolver rate limits, or NXDOMAIN for the name on that resolver can cause a failed panel while others succeed — retry after a minute.

Should I lower TTL before a migration?

Best practice is lowering TTL at least one full prior-TTL period before the change so caches expire faster. This tool helps verify when new values appear.

Are queries sent from my browser?

Yes — each resolver is queried via DNS-over-HTTPS from your browser, same as DNS Lookup.

Can I compare NS delegation during a registrar transfer?

Yes — choose NS type to confirm all resolvers see your intended nameserver set before closing a ticket.

Is this useful for email MX cutovers?

Absolutely — select MX and verify all resolvers list the new mail exchangers with correct priorities before decommissioning old mail servers.