All you need to know about Linux whois command (domain lookup)

  • Domain names (e.g. google.com)
  • IP address (e.g. 216.58.208.78)
  • ASN (Autonomous System Numbers) (e.g. AS15169)

Registries and Registrars

When you lookup a domain name (e.g. google.com) using the command “whois google.com”, you will probably end up with the following result:

whois google.com
Two-level WHOIS record organization
Thick WHOIS record for google.com
  1. Get the thin record from the registry.
  2. Extract the registrar’s whois server from the thin record and get the thick record from registrar’s who is server.
  • Sometimes, thick record does not mention the whois server to lookup. You may need to use your wit to find the whois server based on the registrar’s name.
  • Some registrars explicitly block whois lookup from command line (e.g. whois.godaddy.com). They provide web based lookup with CAPTCHA protection — you need to manually look it up — no automation. It makes sense have such rate limitations to prevent DoS attacks on whois servers maintained by registrars.

--

--

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store
Digest

Digest

59 Followers

One Digest At a Time. I value your time! #datascience #dataanalyst #datascientist #probability #statistics #ML #AI #savetime #digest