How to Perform a WHOIS Lookup
A WHOIS lookup returns the registration details behind a domain name — who registered it, with which registrar, when it expires, its nameservers, and its current status. It is the quickest way to check an expiry date, spot a registrar lock, or investigate an unfamiliar domain. Here is how to run one and read the results.
What a WHOIS lookup shows
A WHOIS record typically includes:
- Registrar — the company the domain is registered through.
- Creation, updated, and expiry dates — when it was registered and when it must be renewed.
- Nameservers — the authoritative nameservers the domain is delegated to.
- Status (EPP) codes — flags such as
clientTransferProhibitedthat indicate locks. - Registrant contact — often redacted behind privacy protection (see below).
How to run a WHOIS lookup
On macOS or Linux, the whois command is built in:
On Windows, use the Sysinternals whois utility or any web-based WHOIS tool — your registrar and most domain registrars offer one. Web tools are the easiest option if you just need a quick answer.
Reading status codes and privacy
The status field uses EPP codes. clientTransferProhibited means a registrar lock is in place — a good thing, as it blocks unauthorized transfers. Codes like pendingDelete or redemptionPeriod signal a domain that has lapsed. Since GDPR, registrant contact details are usually redacted, but the technical fields you most often need — registrar, dates, nameservers, and status — stay visible.
Modern lookups increasingly use RDAP, the structured successor to WHOIS, which returns the same data as JSON. Most tools fall back to it automatically.
Monitor expiry and registration changes
A one-off lookup is a snapshot; the risk is what changes after you check. A missed renewal, an unexpected registrar transfer, or a lock being removed can all signal trouble. ZoneWatcher's domain registration monitoring tracks WHOIS for you — the WHOIS expiry monitor warns you well ahead of expiry, and the domain lock monitor alerts you if the lock state changes.