DNS lookup
Verify DNS changes, debug resolution problems and compare answers between resolvers.
How it measures
- Queries go to the selected public resolver with a 4-second timeout and two tries.
- Answer sets are normalized: sorted, lower-cased, trailing dots removed, MX priorities included, so two queries can be compared without false differences from ordering.
- No records (NODATA), non-existent names (NXDOMAIN) and resolver failures are reported as different outcomes.
Limits
- Public resolvers cache answers; a change may take up to the record TTL to appear.
- Results reflect the resolver's view, not every network's view.
- Reverse lookups and zone transfers are not supported.
Troubleshooting
- NXDOMAIN
- The name does not exist at the authoritative servers. Check for typos and whether the record was published in the right zone.
- No records
- The name exists but has no record of this type. For example, a CNAME-only name has no A record of its own.
- Different resolvers disagree
- Propagation is in progress or a resolver is serving a stale cache. Compare with the authoritative name servers (NS).