WHOIS is a widely used internet protocol and lookup service that allows users to query databases containing information about the registration and ownership of domain names, IP addresses, and autonomous systems. The term “WHOIS” comes from the question “who is responsible for a domain name or IP resource?” and serves as a central directory—often called the internet’s “phonebook”—for finding out who owns a domain and obtaining key registration details.
What Information Does WHOIS Provide?
A WHOIS lookup can reveal a variety of information, including:
• Domain registrant’s contact details (name, email, phone, address—unless privacy protection is enabled)
• Domain registrar (the company managing the domain registration)
• Domain registration and expiration dates
• Nameserver information
• Domain status (active, expired, suspended, etc.)
• Administrative and technical contacts
This information is essential for verifying domain ownership, investigating domain history, conducting legal or security research, and troubleshooting network issues.
How Does WHOIS Work?
- User Query:
A user submits a WHOIS query for a specific domain name or IP address using a web-based tool, command-line utility, or dedicated WHOIS client. - Query Routing:
• For domain names, the query is first sent to the top-level domain (TLD) registry’s WHOIS server (e.g., .com, .org), which may then direct it to the registrar’s WHOIS server for more detailed information.
• For IP addresses, the query is routed to the appropriate Regional Internet Registry (RIR), such as ARIN, RIPE NCC, APNIC, LACNIC, or AFRINIC. - Data Retrieval:
The WHOIS server responds with the requested registration data in a human-readable format. If privacy protection is enabled, some details (like the registrant’s contact information) may be masked. - Data Maintenance:
The WHOIS database is maintained by domain registrars and overseen by the Internet Corporation for Assigned Names and Numbers (ICANN). Registrants are required to keep their contact information accurate and up to date, and ICANN enforces this through regular verification protocols.