Which resolvers does your network use?

This fires a handful of unique, uncacheable names at our authoritative DNS server. Your network's own resolvers have to come ask us for each one — so we see the resolver IPs doing the asking, and can show you which DNS services sit between you and the internet.

Standard sends 6 lookups in one round; Extended sends 6 rounds of 6 to surface resolver pools. We only ever see the resolver IPs — never you, and the test names carry no data.