What database can provide contact information for Internet domains?

dig (Domain Information Groper) is a DNS diagnostic tool that queries nameservers for DNS resource records such as A, MX, and TXT records, but does not access domain registration or contact information.

'who' is a Linux/Unix command that displays a list of users currently logged into the local system and has no connection to Internet domain databases.

WHOIS (written here as 'who is') is a TCP-based query protocol and associated distributed database maintained by domain registrars and regional internet registries such as ARIN and ICANN. It stores and returns registrant contact details, administrative and technical contacts, nameserver assignments, registration dates, and expiry dates for registered Internet domains, making it the authoritative source for domain contact lookups.

nslookup queries DNS servers to resolve hostnames to IP addresses and vice versa, but does not retrieve domain registration, ownership, or contact information stored in WHOIS databases.