The DNS Core Census is an ICANN project to gather information about top-level-domains (TLDs). This covers ccTLDs, gTLDs, effective TLDs (like
co.uk), and entries in
arpa. The census contains information about the zone, like metadata and contractual information, about the name servers, about addresses of the name servers, and the route origins. The data is kept for a 35-day rolling window.