WHOIS

Synopsis

WHOIS [/?] [/V[+|-]] [/SERVER name] [/H name] [/BYIP[+|-]] [/SRV_SUPERDOMAINS[+|-]] [/SRV_SELF[+|-]] [/IMPLICIT[+|-]] [/IP6ADDR[+|-]] [/WHOIS_SUPERDOMAINS[+|-]] [/WHOIS_SELF[+|-]] domains

Description

WHOIS is a client of the NICNAME service (unofficially also known as the "WHOIS" service, after the name of the client). For each domain, it looks up and contacts a NICNAME server, sends a request for that domain, and prints the server's response.

Server location

Unlike other NICNAME clients, WHOIS does not require huge and unwieldy configuration files, that require maintenance as registries come and go, in order to determine where NICNAME servers are.

WHOIS employs modern server location mechanisms and locates NICNAME servers automatically using the DNS, allowing registries to publish and to change the locations of their NICNAME servers without having to update the configurations of all of the NICNAME clients in the world.

WHOIS locates servers from the server string supplied in the normal way, using nicname as the service name, tcp as the transport name, and 43 as the well-known port number; with the following two additions to the standard lookup, which are performed after trying service lookups and immediately before falling back to "implicit" lookup:

  1. If the /WHOIS_SELF option has been enabled, the client issues A/AAAA queries for the combination of the fully qualified domain name itself and the suffix whois-servers.net. &mdash e.g. example.org.whois-servers.net. for the domain example.org.

    If the response to those queries is a success, the IP addresses obtained from the DNS in conjunction with the well-known port become the list of servers to contact, with the ports and weights set to zero, and lookup stops here.

  2. If the /WHOIS_SUPERDOMAINS option has been enabled, the client issues zero or more A/AAAA queries for the combination of progressively shorter superdomains of the fully qualified domain name, all of the way up to the root, and the suffix whois-servers.net. &mdash e.g. co.uk.whois-servers.net., uk.whois-servers.net., and whois-servers.net. for the domain example.co.uk..

    If the response to any of those queries is a success, the IP addresses obtained from the DNS in conjunction with the well-known port become the list of servers to contact, with the ports and weights set to zero, and lookup stops here.

Command-specific options

/V
Display information about the server(s) being contacted.
/SERVER name
Specify the NICNAME server to use.
/H name
Alternative spelling of /SERVER, for compatibility.

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