What is a WHOIS lookup?
A WHOIS lookup asks a domain's registry for its registration record: the registrar, the creation, update and expiry dates, status codes and name servers. Since 2025 the modern protocol for this is RDAP, which returns the same facts as structured data; this tool uses RDAP first and falls back to classic WHOIS.
What the WHOIS result tells you
| Field | What it means |
|---|---|
| Registrar | The company the domain is registered through — where it is renewed, transferred and where its name servers are set. |
| Created | The date the domain was first registered. Domain age is counted from here. |
| Last updated | The last time the registration record changed, for example a renewal, a transfer or new name servers. |
| Expires | The date the registration lapses unless it is renewed. After it, the domain stops working within days. |
| Status codes | Locks and states set by the registrar (client…) or the registry (server…), such as transfer protection or a suspension. |
| Name servers | The DNS servers that answer for the domain. If these are wrong, nothing on the domain resolves. |
Owner names, emails and addresses are usually not shown any more. Since the GDPR took effect in 2018, most registries and registrars redact personal contact data, and most domains also use a privacy service. To reach the owner, use the registrar's contact form or the abuse contact it publishes.
How to check domain age
Domain age is the time since the created date. The tool works it out in years and months. Age is a common trust signal: phishing and scam sites are usually registered days or weeks before they are used, while a business domain is typically years old.
Two caveats. The created date resets if a domain expires, is deleted and is then registered again by someone else, so an old name can have a young record. And age says nothing about who owns it now — a domain can change hands without its created date moving.
WHOIS vs RDAP
Classic WHOIS (port 43) returns free text whose layout differs by registry, with no standard date format and strict rate limits. RDAP (Registration Data Access Protocol) replaced it: JSON over HTTPS, the same fields everywhere, and a bootstrap file from IANA that says which server holds each top-level domain. ICANN ended the WHOIS requirement for generic top-level domains in January 2025.
This WHOIS lookup asks RDAP first. For country-code domains whose registry has no RDAP service yet, it falls back to that registry's WHOIS server and reads the expiry date from the text. Those results are marked "WHOIS (port 43)" and show fewer fields. The same engine powers the RDAP lookup and the bulk domain expiry checker.
Domain status codes explained
| Status | Meaning | Action needed? |
|---|---|---|
clientTransferProhibited | Registrar lock against unauthorized transfers | No — this is normal protection |
clientHold / serverHold | Suspended; the domain does not resolve | Yes — contact the registrar |
redemptionPeriod | Expired and deleted, still restorable for a fee | Yes — restore it now if it is yours |
pendingDelete | About to be released for anyone to register | Too late to renew; it can be re-registered after release |
autoRenewPeriod | The registry has just renewed it | Check the registrar charged a valid card |
inactive | No name servers set | Set name servers if the domain should be used |
Never let a domain expire by accident
An expired domain takes the website, email and certificate renewals down together, and certificate authorities cannot validate a domain whose DNS has stopped. The usual cause is not forgetting to pay but an expired card on auto-renew or a renewal notice going to a former employee's mailbox.
- Turn on auto-renew and check the card on file once a quarter.
- Set the registrant email to a shared address, not one person's inbox.
- Watch the expiry date somewhere you already look. NetworkAI's monitor checks registration and certificate expiry every day and alerts you by email, Slack or webhook — free for 5 domains.
For a full picture of a domain — certificates, DNS, email authentication and expiry — run the domain health check. To see where DNS for the domain is served, use the NS lookup.
$ whois example.com # classic WHOIS from a terminal
$ curl -s https://rdap.org/domain/example.com # the same data via RDAP