How to debug network issues in Unix — “whois”

2 min readMay 10, 2021

In my day-by-day job, I started to use lots of BASH commands to debug network issues, and I did never not many of them. This is why I decided to write here all those commands and how do I use usually.

This is a series. Here the table of contents:

Today we will talk about whois.

With whois you could know details about who owns a specific domain, or the IP address related to. To do that, this command looks up records in databases maintained by several Network Information Centers (NICs), like Internet Assigned Numbers Authority (IANA), American Registry for Internet Numbers (ARIN) or Réseaux IP Européens (RIPE).

Giving the domain or the IP address, whois will provide you details on organization, contact name, name servers, etc.

$ whois www.example.com% IANA WHOIS server
% for more information on IANA, visit http://www.iana.org
% This query returned 1 object
domain:       EXAMPLE.COM
organisation: Internet Assigned Numbers Authority
created:      1992-01-01
source:       IANA
$ whois 93.184.216.34% IANA WHOIS server
% for more information on IANA, visit http://www.iana.org% This query returned 1 object
refer:        whois.ripe.net
inetnum:      93.0.0.0 - 93.255.255.255
organisation: RIPE NCC
status:       ALLOCATED
whois:        whois.ripe.net
changed:      2007-03
source:       IANA% This is the RIPE Database query service.% The objects are in RPSL format.
%
% The RIPE Database is subject to Terms and Conditions.
% See http://www.ripe.net/db/support/db-terms-conditions.pdf
% Note: this output has been filtered.%       To receive output for a database update, use the "-B" flag.
% Information related to '93.184.216.0 - 93.184.216.255'
% Abuse contact for '93.184.216.0 - 93.184.216.255' is 'abuse@verizondigitalmedia.com'inetnum:        93.184.216.0 - 93.184.216.255
netname:        EDGECAST-NETBLK-03
descr:          NETBLK-03-EU-93-184-216-0-24
country:        EU
admin-c:        DS7892-RIPE
tech-c:         DS7892-RIPE
status:         ASSIGNED PA
mnt-by:         MNT-EDGECAST
created:        2012-06-22T21:48:41Z
last-modified:  2012-06-22T21:48:41Z
source:         RIPE # Filtered
person:         Derrick Sawyer
address:        13031 W Jefferson Blvd #900, Los Angeles, CA 90094
phone:          +18773343236
nic-hdl:        DS7892-RIPE
created:        2010-08-25T18:44:19Z
last-modified:  2017-03-03T09:06:18Z
source:         RIPE
mnt-by:         MNT-EDGECAST
% This query was served by the RIPE Database Query Service version 1.94.1 (HEREFORD)

Originally published at https://gabriele-decapoa.github.io.

How to debug network issues in Unix — “whois”

Written by Gabriele de Capoa