Nameserver lookup
Every DNS answer about your domain comes from its nameservers. Knowing which they are tells you who can change your records, who to contact when resolution breaks, and whether one outage takes everything down.
Free, no signup, no daily limit. We do not store what you check here.
Concentration is the risk nobody measures
Four nameservers sound redundant until you notice all four belong to the same provider, in which case they fail together. The large DNS outages of the last decade took down thousands of domains that each believed they had redundancy. Spreading across two operators is the only version of this that survives a provider incident, and it costs nothing beyond the configuration.
The delegation can disagree with the zone
The nameservers listed at the registry and the NS records inside the zone are two separate things, and they drift after a migration. Resolvers follow the registry, so a zone that lists new nameservers while the registry still points at the old ones behaves unpredictably: some answers come from a server nobody is updating any more.
Questions
How many nameservers should I have?
Two is the minimum most registries accept; four is common. The number matters far less than whether they share a failure domain — four from one provider is less resilient than two from two.
Why does a nameserver answer for a domain I moved away from?
Because it still has the old zone loaded and nobody removed it. Until the registry delegation is updated everywhere and caches expire, both sets can answer, and they will not agree.
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MX record lookup
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When you need more than a free tool
This page answers what can be determined offline and from public DNS. The API adds live carrier and mailbox verification, a calibrated confidence score, and the full evidence trail behind every verdict.
Credits never expire. Inconclusive verdicts are never billed. Cancel in one call. See pricing or read the docs.