root@thehacksparrow:~/writeups$ SYSTEM ONLINE
root@sparrow:~/writeups$ cat whois.md
// tools

Whois

22 Jul 2026 · 2 min read

What it is — Whois queries a domain's public registration record: who registered it, when, with which registrar, and (if not hidden behind privacy protection) the associated contact details. It's one of the oldest and most basic queries in all OSINT recon, and still the mandatory first step.

TypeCLI + web services
CostFree
Web alternativewho.is

How to use it

whois domain.com

If whois isn't installed:

sudo apt install whois

Many modern domains use WHOIS privacy protection (a registrar service that hides the real owner's data) — in those cases you'll see generic details from the privacy provider instead of the actual person/company. Even so, the registration date, registrar, and nameservers remain useful.

What it reveals

  • Domain registration and expiry dates
  • Registrar (GoDaddy, Namecheap, Cloudflare...)
  • Assigned nameservers (DNS)
  • Owner contact details, if not protected by privacy
  • Recent change history on some services (useful for spotting freshly registered domains, typical in phishing campaigns)

What I use it for

  • First check on a suspicious domain: a domain registered a few days ago is a classic red flag in phishing triage.
  • Confirming infrastructure ownership before assuming a domain actually belongs to the organisation I'm auditing.
  • Recon starting point — alongside crt.sh and DNSDumpster, it's always one of the first queries I run on a new target.