Each registered domains have record in whois database with basic informations about domain owner. If owner of domain bought "domain privacy" then in whoIs not avaible information about owner. Any extension of domain have own whoIs database, also huge registars like Godaddy, Network Solutions have additional database.
Whois records include basic informations about domain owner, domain status and dns servers. Usually available also date and time when domain been registered, updated and when expiring. If registar of domain have own whois server then also record include url to this whois server and in this case details about domain owner include only at registar whois.
Type domain name bellow and click CHECK button to obtain whoIs record.

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