The WHOIS protocol had its origin in the ARPANET NICNAME protocol and was based on the NAME/FINGER Protocol, described in RFC 742 (1977). The NICNAME/WHOIS protocol was first described in RFC 812 in 1982 by Ken Harrenstien and Vic White of the Network Information Center at SRI International.
WHOIS was originally implemented on the Network Control Program (NCP) but found its major use when the TCP/IP suite was standardized across the ARPANET and later the Internet.
Connect to the service host
TCP: service port 43 decimal
NCP: ICP to socket 43 decimal, establishing two 8-bit connections
Send a single "command line", ending with <CRLF>.
Receive information in response to the command line. The
server closes its connections as soon as the output is
finished.