WHOIS is a query and response protocol used to lookup registered domain owners, registrar details, nameservers, and expiration dates.
WHOIS (pronounced "who is") is a transaction-oriented query and response protocol standardized by the Internet Engineering Task Force (IETF) in RFC 3912. Established in the early days of ARPANET and governed globally by the Internet Corporation for Assigned Names and Numbers (ICANN), WHOIS enables network administrators, security researchers, and trademark owners to query authoritative databases to identify the legal registrants, hosting registrars, autonomous system numbers (ASNs), creation timestamps, and authoritative DNS nameservers of domain names and IP address blocks.
Perform instant domain ownership and registrar lookups using our client-side Domain WHOIS Lookup tool.
| Specification | Traditional WHOIS | Modern RDAP |
|---|---|---|
| Standard Reference | IETF RFC 3912 | IETF RFC 7480 / RFC 7481 / RFC 7482 / RFC 7483 |
| Default Port | Port 43 (Plaintext TCP socket) | Port 443 (HTTPS REST API) |
| Response Format | Free-form, unstructured plain text | Standardized, machine-parseable JSON |
| Internationalization | US-ASCII only | Full UTF-8 and IDN support |
| Access Control & Auth | None (Anonymous access) | Role-based access control (RBAC) |
| Governing Body | ICANN (Global coordination) | ICANN & Regional Internet Registries (RIRs) |
Querying a domain via the WHOIS protocol returns structured registration milestones:
Domain Name: DEVFLOW.TOOLS
Registry Domain ID: D12345678-LROR
Registrar WHOIS Server: whois.cloudflare.com
Registrar URL: http://www.cloudflare.com
Updated Date: 2026-01-15T08:30:00Z
Creation Date: 2024-03-20T14:15:22Z
Registry Expiry Date: 2027-03-20T14:15:22Z
Registrar: Cloudflare, Inc.
Registrar IANA ID: 1910
Domain Status: clientTransferProhibited https://icann.org/epp#clientTransferProhibited
Registry Registrant ID: REDACTED FOR PRIVACY
Registrant Name: REDACTED FOR PRIVACY
Registrant Organization: Privacy Protection Service
Registrant Country: US
Name Server: CLOE.NS.CLOUDFLARE.COM
Name Server: SKIP.NS.CLOUDFLARE.COM
DNSSEC: signedDelegation
Historically, WHOIS queries returned the personal phone numbers, physical street addresses, and personal email addresses of individual domain owners.
Following the European Union's General Data Protection Regulation (GDPR) in 2018:
"REDACTED FOR PRIVACY".Because RFC 3912 WHOIS uses an unstructured text output on Port 43, writing parsers was notoriously brittle across hundreds of generic TLDs (.com, .org, .tools).
ICANN has officially mandated that domain registries transition to the Registration Data Access Protocol (RDAP):
GET https://rdap.org/domain/devflow.tools).clientTransferProhibited status mean in WHOIS?This Extensible Provisioning Protocol (EPP) status code—also known as a Registrar Lock—is a security measure that prevents unauthorized third parties from transferring the domain name to another registrar without the account owner unlocking it first.
Yes. When a domain reaches its Registry Expiry Date, it enters an auto-renew grace period (typically 30–45 days), followed by a 30-day Redemption Period, and a 5-day Pending Delete phase before being released back into the public registration pool.
Input any web address into our Domain WHOIS Lookup to inspect domain age, expiration dates, and authoritative nameservers without installing CLI packages.
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