What is DNS propagation?

DNS propagation is the time it takes for a DNS record change to become visible to resolvers around the world. Every recursive resolver caches records for the duration of the record's TTL (time to live). Until each cache expires, resolvers keep returning the old answer — which is why a freshly-updated record can be live at one resolver and stale at another for minutes, hours, or even days.

WhereIsDNS queries 12 public DNS resolvers in parallel and shows you exactly which ones see the new record and which still have the old one cached. It's the fastest way to confirm a domain change has gone global.

Resolvers we check

Every lookup hits all 12 of these public DNS resolvers simultaneously over DNS-over-HTTPS:

Supported record types

WhereIsDNS supports the most common DNS record types: A (IPv4), AAAA (IPv6), CNAME (alias), MX (mail servers), NS (nameservers), TXT (text records, including SPF and DMARC), SOA (start of authority), CAA (certificate authority authorization), and PTR (reverse DNS).

Frequently asked questions

How long does DNS propagation take?

Most propagation completes within minutes to a few hours. The upper bound is the record's TTL — commonly 300 seconds (5 minutes) to 86400 seconds (24 hours). Some ISP resolvers ignore short TTLs and cache for longer, which is why a small number of resolvers can lag for a day or more after a change.

Why do different DNS resolvers show different results?

Each resolver caches independently. When you change a DNS record, resolvers that already had the old record cached keep serving it until their TTL expires. Resolvers that had no cached entry fetch the new record immediately. Geo-aware DNS (GeoDNS) can also legitimately return different answers to resolvers in different regions — that's by design, not a propagation problem.

What is a TTL in DNS?

TTL (time to live) is the number of seconds a resolver is allowed to cache a DNS record before re-fetching it from the authoritative nameserver. Lower TTLs mean faster propagation but more queries against your nameservers; higher TTLs mean slower propagation but better performance and lower load. A common pattern is to lower the TTL to 300 seconds 24 hours before a planned change, then raise it back afterward.

What does NXDOMAIN mean?

NXDOMAIN ("non-existent domain") is the DNS response code that says the queried name does not exist. If WhereIsDNS shows NXDOMAIN across most resolvers, either the domain is not registered, the record type you searched for doesn't exist on that name, or you're checking a subdomain that hasn't been published.

How do I speed up DNS propagation?

You can't force someone else's resolver to drop its cache, but you can shorten the window before a change by lowering the record's TTL well in advance. End users can flush their local DNS cache (ipconfig /flushdns on Windows, sudo dscacheutil -flushcache on macOS) but that only clears their own machine.

Is WhereIsDNS free?

Yes. No signup, no rate limits for normal use. Supported by AdSense.

How WhereIsDNS works

A request from your browser hits a Cloudflare Worker, which fans out 12 DNS-over-HTTPS queries — one to each public resolver — in parallel. Each resolver's answer is streamed back to your browser via Server-Sent Events the moment it arrives, so the slowest resolver doesn't hold up the rest. Total round trip is typically 200–500 ms.

Caveat on geography: the location labels reflect each resolver operator's nominal jurisdiction, not a multi-vantage probe — the query itself originates from the Cloudflare edge nearest the user. For most propagation troubleshooting this is enough; if you need physical-location vantage points, look for a tool that runs probes from rented servers in different cities.