About the DNS Resolver Comparison
The DNS resolver comparison tool queries four public recursive resolvers and normalizes their answers side by side. It is useful after DNS changes or when users on different networks report inconsistent results.
How to use this tool
Enter a public domain, choose a supported record type, and compare the results returned by Cloudflare, Google, Quad9, and OpenDNS. Start with the exact hostname and record type involved in the issue. Recheck after the previous TTL has elapsed, and compare the resolver answers with the authoritative record configured at your DNS provider. Differences can be temporary during a change or intentional when DNS responses vary by location or policy.
How to read the result
Matching normalized answers indicate that the selected resolvers currently agree, not that every resolver worldwide has the same cache. A missing or different answer can reflect a stale cache, negative caching, DNSSEC validation behavior, filtering, geography, or resolver-specific policy. MX preference values, CNAME targets, and the complete TXT strings matter when comparing data. Use timestamps and TTL context when documenting propagation rather than relying on the word propagated alone.
Limits and privacy
The comparison covers four named public resolvers from the buffer.lol server's network location. It does not query ISP, enterprise, device, or authoritative resolvers and cannot represent every geographic edge. DNS answers may change immediately after the check. The submitted domain and record type are processed by the same-origin diagnostics API and sent to the selected public resolver endpoints only for this request.
Common questions
- Why do public DNS resolvers return different answers?
- They may hold caches created at different times, apply different validation or filtering policies, or reach geographically varied authoritative infrastructure.
- Does agreement mean DNS propagation is complete?
- It means these four resolvers agree at the time of the test. Other recursive resolvers may still have different cached data.