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Free tool

Do all nameservers of this zone actually work?

Each nameserver listed for the domain is asked for the zone directly. One that does not answer, is not authoritative or serves an older serial makes some of your visitors see errors or stale records, at random.

What this checks

Lame delegations and stale secondaries

A delegation lists the nameservers of a zone; resolvers pick one at random for each query. A listed server that does not know the zone ("lame") returns an error or a referral, a server with an old serial returns old data. Both show up as intermittent problems that are hard to reproduce. This check asks each server directly, bypassing caches, for the zone's SOA record and compares what comes back.

Related tools

More in this set

  • DNS lookup Any record type of any name, with TTLs.
  • DNS propagation Has your change reached the public resolvers yet?
  • DNSSEC check DS at the parent, DNSKEY in the zone, and whether they match.
  • Reverse DNS check PTR record of an address and whether it confirms forward.
  • Domain info Registrar, expiry date, status and nameservers from the registry.

All tools Glossary

Domains and DNS

Domains with DNS hosting included

Register or transfer .lu, .eu, .be, .com and more; the DNS editor, DNSSEC and the records these tools check are in the client area.

See domains