About our measurement queries

If you found this page from a reverse DNS lookup, you’re looking at a research host we run. We’re measuring which IP addresses the world’s registered domains resolve to, using the zone files ICANN publishes through its Centralized Zone Data Service. Our authoritative rail sends one ordinary A-record question per domain directly to the domain’s nameserver, with strict limits per server, network and operator. A separate recursive baseline asks for apex A, AAAA and MX records through Google Public DNS and Cloudflare 1.1.1.1, capped at 500 questions per second to each service from this single disclosed research host. We do not send EDNS Client Subnet, spoofed traffic, vulnerability probes or amplification queries, and every observation is kept with the resolver that supplied it.

If it’s causing you any trouble at all, write to abuse@dnscensus.org — a person reads it and will act on it.