Every registered domain has associated records containing essential details about its owner, registrar, and technical information. WHOIS is a publicly accessible database that allows users to retrieve these details about domain names. In this article, we will explain how WHOIS works, what information it provides, and how to protect your data.
What is WHOIS?
WHOIS is an internet protocol and database system that allows querying information about domain names, their owners, and registrars. It is used to identify domain owners and verify technical details required for DNS management.
How Does WHOIS Work?
- A user submits a WHOIS query for a domain name.
- The WHOIS server returns domain records, including the registrar, registration and expiration dates, and possibly owner information (if not hidden).
- Users can check domain availability or review its history.
WHOIS queries can be performed in different ways:
- Through web-based tools – such as whois.domaintools.com, whois.net, or ICANN WHOIS.
- Via terminal commands – On Linux or macOS, you can use: whois example.com
- Using API services – Some online services offer APIs for automated WHOIS queries.
What Information Does WHOIS Provide?
WHOIS records contain several key details:
- Domain name – e.g.,
example.com. - Domain status – Active, expired, locked for transfer, etc.
- Registration and expiration dates – When the domain was registered and when it will expire.
- Registrar information – The company where the domain was registered.
- Registrant contact details (if not hidden).
- Name servers – The DNS servers that manage the domain.
WHOIS Privacy Protection
Due to privacy concerns, many registrars offer "WHOIS Privacy" (also called Domain Privacy Protection). This service hides personal information of the domain owner and replaces it with anonymized contact details.
For .CZ domains, the CZ.NIC registry automatically hides personal data for individuals, while corporate entities remain publicly visible.
When is WHOIS Used?
- Checking domain availability – To see if a domain is available for registration.
- Contacting a domain owner – For inquiries or domain purchase offers.
- Retrieving technical information – To check DNS configuration or server details.
- Investigating cyber threats – WHOIS helps identify owners of phishing or fraudulent domains.
Disadvantages of WHOIS and the Future of Domain Lookup
| WHOIS Advantages | WHOIS Disadvantages |
|---|---|
| Quick domain availability checks | Limited data visibility due to GDPR |
| Helps improve cybersecurity | Public records can be misused (spam, fraud) |
| Useful for domain management | Some registrars allow full data concealment |
Due to GDPR and increasing privacy regulations, WHOIS records are becoming more restricted and anonymized. In the future, WHOIS may be replaced by alternative verification methods such as RDAP (Registration Data Access Protocol).
WHOIS is a vital tool for domain name management, allowing users to retrieve information about domains, registrars, and technical settings. Although data access is being restricted due to privacy laws, WHOIS remains essential for verifying domain ownership and online security. If you own a domain, consider enabling WHOIS Privacy to protect your personal data, if supported by your registrar.
