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What Is WHOIS?

WHOIS is a query-and-response protocol used to look up publicly available registration information about domain names and IP addresses. When you perform a WHOIS lookup, you can retrieve details such as the registrant’s name, organization, contact information, registration and expiration dates, and the registrar or registry responsible for the record.

Originally developed in the early days of the internet, WHOIS remains a widely used tool for network administrators, security researchers, and anyone investigating IP address ownership or tracing the source of suspicious activity online. It pulls data from a distributed network of databases maintained by regional internet registries and domain registrars. 

WHOIS results can vary depending on the domain extension and regional policies. Many registrants now use privacy protection services that mask personal details while still satisfying registration requirements. For a deeper layer of network analysis, WHOIS is often used alongside DNS lookups to build a clearer picture of how a domain or IP is configured and managed.