thinQmaster Virtual testing partner Adaptive practice exams that find your weak spots and drill them. Every answer explained. From $69
Enroll

thinQmaster

Find your exam

Five questions free, before you decide.

Step 1 · choose a vendor

In one of our camps? Your practice exams come with the tuition — they are on your study page already.

Application & OT Security · Foundational

WHOIS

A query protocol and database that returns registration details for domain names and IP address blocks.

Definition

WHOIS records can reveal registrar, registration and expiry dates, name servers and sometimes registrant contacts, though GDPR-era redaction now hides many personal details. Regional Internet Registries such as ARIN provide IP block ownership. RDAP is the modern JSON-based successor protocol.

Example

whois example.com reveals the registrar and authoritative name servers.

Exam tip

WHOIS is passive recon; the modern replacement protocol is RDAP.

Related terms