Lookups and data
Zone file
A zone file is the registry's list of every domain in an extension that has nameservers, with those nameservers. The .com zone has well over 160 million names.
What Zone file means in practice
The registry publishes the file so the DNS can find every name. For .com, approved users can download a daily copy through ICANN's Centralized Zone Data Service (CZDS), under terms that forbid passing the list on.
Only names with nameservers are in it. A name that is registered without nameservers, or on hold, is not listed, so a name missing from the zone may still be taken.
Why it matters
The zone is the best public record of which names exist, and comparing two days shows which names appeared and which left. The numbers are on the State of .com page.
Try it
- Deleted Domains Names that appeared in, or left, the .com zone since the last snapshot, filtered by a keyword.
- Naming Patterns How many .coms start with, end with or contain a word like "ai" or "hub"?
- Hosting Stats Who runs the DNS for 167 million .com names, and who runs yours.
- Availability Checker Check up to 50 names at once: taken, available, or about to drop.
Related terms
- Registry A registry is the organisation that runs one top-level domain and keeps the master database of its names. Verisign is the registry for .com.
- Nameserver A nameserver is a server that holds a domain's DNS records and answers questions about it. A domain lists at least two so one can fail.
- RDAP RDAP, the Registration Data Access Protocol, is the standard way to look up whether a domain is registered and its status. It replaced WHOIS.