WHOIS is a protocol for querying databases that store domain registration information. WHOIS data reveals who owns a domain, when it was registered, when it expires, and which nameservers it uses. This information is valuable for research, security, and domain acquisition.
WHOIS Data Fields
WHOIS records contain registrant information (name, organization, email), registrar details (the company that registered the domain), important dates (creation, expiration, last update), nameserver information, and domain status codes. However, GDPR and privacy regulations have restricted access to personal registrant data for many TLDs.
Domain Privacy and GDPR
Many registrants use privacy protection services that replace their personal information with proxy data. GDPR (effective 2018) requires registrars to redact personal information from WHOIS for .com, .net, and other TLDs. Business registrations may still show full details. This makes WHOIS less useful for finding domain owner contact information than in the past.
Domain Status Codes
WHOIS returns status codes like clientTransferProhibited (domain can't be transferred without authorization), serverHold (domain is suspended), pendingDelete (domain is expiring soon), and ok (domain is active with no special restrictions). These codes indicate the domain's operational state and any restrictions.
Using WHOIS for Domain Research
WHOIS is valuable for checking domain expiration dates (for acquisition opportunities), verifying nameserver configuration, researching domain age for SEO analysis, and identifying the registrar for transfer purposes. Combine WHOIS with DNS lookups for comprehensive domain intelligence.