Описание тега whois
The WHOIS protocol allows a user to query the registrant of a particular domain name or IP address.
The WHOIS service is a TCP based protocol that allows you to look up the registrant of a domain name.
The WHOIS service sits on TCP port 43 and can often be found at whois.nic.tld (where 'tld' is replaced with the appropriate top-level domain such as .it or .xyz).
One way to use it is to simply telnet to it and send the domain name followed with at CRLF. For example:
telnet whois.nic.coop 43 midcounties.coop
You will then get a list of all the details about the domain.