WHOIS is a query and response protocol used to query databases that store registered users or recipients of an Internet resource, such as a domain name, IP address block, or autonomous system, but it is also used for a wider range of other information.

Since November 2011, CARNET has been maintaining its WHOIS service, which can be accessed using the whois.dns.hr server. Information about the WHOIS server is also entered in the root DNS zone maintained by - IANA.

Example - the client that comes inside the Debian distribution (the current stable distribution). It is a program that is run from within the command line.

To check the version of the program, we use the following command:

$ whois --version
Version 5.3.0.
Report bugs to <md+whois@linux.it>

Try searching a domain within the .hr domain:

$ whois carnet.hr
Domain Name: carnet.hr
Registrar WHOIS Server: whois.dns.hr
Registrar URL: http://whois.dns.hr
Updated Date: 2019-05-14T22:00:00Z
Creation Date: 2001-12-12T23:00:00Z
Registrar Registration Expiration Date: 2050-11-15T23:00:00Z
Registrant Name: CARNet
Registrant Street: Josipa Marohnića 5
Registrant City: Zagreb
Registrant State/Province: HR
Registrant Postal Code: 10000
Name Server: dns1.carnet.hr
Name Server: dns2.carnet.hr

It is also an option to add the name of the WHOIS server directly to the command line:

$ whois carnet.hr -h whois.dns.hr

In addition, we note:

all printouts from the whois.dns.hr server are UTF-8, so if there are problems with Croatian diacritical marks, you need to adjust your code side
the server itself internally limits the number of queries that one client can request in order to avoid mass collection of domain data and thus protect the holders of .hr domains