WHOIS Lookup

Network Server-side whois domain ip registrar dns registry lookup

This tool processes your data on the server: whatever you submit here is sent over the network to be processed, then the result is sent back to your browser.

What it does

Performs a real WHOIS query against the authoritative WHOIS server for a domain or IP address. The server first asks the IANA root WHOIS server which registry is responsible for the TLD (or IP block), then follows the referral to query that registry directly — the same way the whois command-line tool works.

Try it

How it works

Your browser sends the domain or IP to /api/tools/whois-lookup.
The server (tools/whois-lookup/server.js) opens a raw TCP socket on port 43 to whois.iana.org to find out which WHOIS server is authoritative for that TLD (or IP allocation, for IPs).
It then connects to that authoritative server and re-sends the query, following one further referral if the response indicates a more specific WHOIS server (common for gTLDs like .com/.net, which are registered with Verisign but often refer further to the registrar's own WHOIS server).
The raw, unparsed WHOIS text response is returned as-is and displayed below, exactly as the WHOIS server sent it.

Why this needs a server

WHOIS is a plain-text protocol running over raw TCP port 43 — there is no HTTP/HTTPS equivalent, and no way for a browser to open an arbitrary TCP socket from JavaScript. This tool has to run server-side to actually speak the WHOIS protocol.

Notes

Some registries (notably .dk, some ccTLDs, and certain registrars) heavily rate-limit or block automated WHOIS queries — a connection refused or empty response is common and does not mean the domain is unregistered.
For privacy-protected domains (WHOIS privacy/proxy services), the registrant's real contact information is intentionally hidden by the registrar; this is expected and not an error.
IP address queries are routed to the appropriate Regional Internet Registry (ARIN, RIPE, APNIC, LACNIC, or AFRINIC) automatically via the IANA referral.