Whois is a tool used to check the registration databases at the Network Information Centers at ARIN, RIPE, APNIC, and all major domain name registrars.

Whois returns the billing address, the administrative phone and e-mail addresses and other information from the central servers. However the whois application is checking the 'registration' database, and not the actual database used for IP addresses or domain names.

You CANNOT use WHOIS (TCP port 43) to check DNS (UDP port 53) resolution; DNS is a separate database accessed using a separate protocol (dig or nslookup).


Whois is available from the command line in some operating systems (Windows does not include whois). To use whois from the command line, type the following:

whois -h <registry host> <query>


Domain Names

NOTE: InetDaemon makes NO ENDORSEMENTS of ANY of these organizations!

IP Addresses (via whois)


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