WHOIS

WHOIS is a query protocol and the associated public database that lets you look up information about the registration of an internet domain. Querying WHOIS reveals when a domain was registered, when it expires, which registrar manages it and which name servers, or DNS servers, are set for it.

What WHOIS is used for

WHOIS is used to check whether a domain is available, to see its expiry date before a purchase, and in diagnostics — when you need to establish who is responsible for a given name's configuration. Administrators use WHOIS during migrations, trademark investigations or analysis of spam-sending domains. The name-server information in WHOIS complements the picture of DNS configuration, though the propagation of changes still depends on the TTL of the records.

WHOIS and privacy

WHOIS once exposed a registrant's full personal data: name, address and phone number. Since GDPR came into force, registrars in Europe mask this data, leaving only technical details and an indirect contact channel public. Many registrars also offer a privacy protection service that replaces the owner's data with that of an intermediary. WHOIS queries can be made through a registrar's website, dedicated online tools or the whois command line. It is worth noting that for newer domains the RDAP protocol is increasingly used; it returns structured data in JSON and is gradually replacing classic WHOIS, keeping its informational role but in a form that is easier to process automatically. All these lookups are typically served over HTTPS when accessed through web interfaces, keeping the query itself private.