DNS Propagation Checker
Query Cloudflare, Google and Quad9 in parallel to see whether a DNS change has propagated. Spot stale caches and inconsistent answers immediately.
Quick answer: Query Cloudflare, Google and Quad9 in parallel to see whether a DNS change has propagated. Spot stale caches and inconsistent answers immediately.
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Frequently asked questions
- How long does DNS propagation take?
- Usually under an hour but it can take up to 48 hours, depending on the TTL of the old record and how aggressively each resolver caches.
- Why does my laptop see different DNS than my phone?
- They're using different resolvers (your home router vs the carrier DNS), and those resolvers may have cached the old or new answer at different moments.
- What's the difference between resolver and nameserver?
- A resolver (Cloudflare 1.1.1.1, Google 8.8.8.8) is the recursive service your computer asks. A nameserver is the authoritative source for a zone (e.g. ns1.yourhost.com).
- How does DNS caching work?
- Each record carries a TTL. After a successful lookup, every resolver and OS along the path stores the answer until that TTL expires.
- Can I lower the TTL before a migration?
- Yes. Drop it to ~300 seconds at least 24 hours before the change so the old TTL has expired everywhere by cutover time. Raise it again after.
- Why does my old IP keep showing up?
- Some resolver, OS, or browser somewhere in the chain is still serving a cached copy. Wait for the TTL or flush local caches.
- How do I force a DNS refresh?
- Flush local caches: sudo dscacheutil -flushcache (macOS), ipconfig /flushdns (Windows), sudo systemd-resolve --flush-caches (Linux). Browsers and routers cache too.
- What is split-horizon DNS?
- Different answers depending on where the query comes from. Common in corporate networks where internal users get private IPs and external users get public ones.
- How do I check whether my new MX is active?
- Pick MX as the record type and run the check. All three resolvers should agree on the new exchange and priority.
- Can I see DNSSEC?
- Not directly here — DNSSEC validation is performed by the resolver. If a resolver refuses to return an answer for a signed zone, that's usually a DNSSEC issue.