NSFrequently asked questions
Practical answers for everyday DNS checks.
Why do resolvers return different answers?
They may hold different cached versions of a record, or receive different answers because of geographic routing or load balancing. Compare authoritative responses and your provider’s configuration when investigating.
Does this test DNS propagation worldwide?
No. The comparison queries Cloudflare, Google, and Quad9 from this application server. It does not sample many geographic locations or every resolver.
What does an empty result mean?
The server may have answered successfully without records of the requested type. NXDOMAIN means the queried name does not exist according to that response. A timeout means an answer was not received in time.
What is authoritative mode?
The engine discovers the domain’s nameservers and queries safe public authoritative endpoints directly. Those answers reflect the zone served there, rather than a public recursive resolver’s cached view.
Can I look up an IP address?
Yes. Enter the address and choose PTR for reverse DNS. The interface also selects PTR when you finish entering an IP address.
Why are there two answers for one provider?
The engine queries the provider’s configured endpoints and shows each response separately. Returned record counts include records from every answering endpoint.
What does the matching summary compare?
It compares record names, types, and values across the three providers, ignoring record order and TTL differences. The summary requires successful responses from all endpoints.
Are there request limits?
The current API allows 15 lookup requests per minute per IP address. A comparison uses three requests. There are also concurrency limits and query timeouts to protect the service.
Can I save or share a result?
Use Copy JSON to save returned data, or Copy link to share the query settings. Opening a link runs a fresh lookup; it does not preserve the original answer.