● RESOLVER COMPARISON

See what selected resolvers
observe for your DNS.

Compare records returned by established public recursive resolvers. Useful for migrations, CDN cutovers, nameserver changes, and email DNS troubleshooting.

OBSERVED RESOLVER RESULTS

AGREEMENT STATE

Resolver comparison

Resolver	Status	Observed values	TTL	Time	Expected

Unique observed values grouped by resolver

TTL interpretation

Need a broader production check?

Run Domain Health Studio after DNS changes to review TLS, redirects, headers, and email authentication together.

Open Domain Health Studio

Understanding DNS propagation

Recursive resolver caches

Different resolvers can retain older answers until their cached TTL expires. Matching record values matter more than small TTL differences.

Authoritative versus observed data

This milestone compares recursive resolvers. A deeper investigation may also query authoritative nameservers under strict controls.

Failure states matter

NXDOMAIN means the name does not exist according to that resolver; SERVFAIL indicates resolution failed. A timeout is unverifiable, not a mismatch.