Glossary Guides

What Is WHOIS

Learn what WHOIS and RDAP are, what registration data they show, domain status codes, and how WHOIS differs from DNS.

By CheckDomainHealth Editorial Team Reviewed by Dionis Ceban Updated Jun 28, 2026 5 min read Beginner

Introduction

WHOIS helps you answer “Is this domain registered? Who is the registrar? When does it expire? What nameservers are set?”

RDAP is the newer structured protocol many registries use alongside or instead of classic WHOIS text output.

Quick answer

WHOIS (and modern RDAP) is a public lookup service that shows domain registration information: registrar, creation and expiry dates, domain status, and nameservers. Privacy services often hide owner contact details.

What it means

WHOIS data comes from the domain registry and registrar. It describes registration metadata — not live DNS records like A or MX (though nameserver hostnames appear).

Registrar — where the domain is managed
Creation and expiry dates — registration lifecycle
Domain status — active, clientHold, redemption, etc.
Nameservers — delegation info (verify with DNS Lookup too)
Privacy/redaction — contact details may be hidden
RDAP — JSON-based modern alternative to WHOIS

Where you see this:

Checking if a domain is available or expired
Finding registrar before renewal or transfer
Investigating domain status problems
Verifying nameserver delegation during DNS troubleshooting

Why this matters

WHOIS answers registration questions DNS alone cannot. Expired domains, registrar holds and wrong registrar login block email and websites even when DNS records look fine.

How to check it

Run WHOIS Lookup on the domain.
Note registrar, expiry date and domain status codes.
Compare nameservers in WHOIS with DNS Lookup NS records.
Check for clientHold, redemption or pending delete statuses.
Use RDAP/WHOIS at registry if registrar view differs.

Look up WHOIS

Use WHOIS Lookup to see registrar, status, dates and nameservers for a domain.

Run WHOIS Lookup →

Common mistakes

Expecting full owner info despite privacy

Low

GDPR and privacy services redact registrant contacts.

Next step: Use registrar abuse contacts or authorized portal access.

Ignoring domain status codes

High

clientHold or serverHold stops DNS from working.

Next step: Resolve hold with registrar before debugging DNS records.

Assuming WHOIS shows live DNS records

Medium

WHOIS nameservers may lag or differ from cached NS answers.

Next step: Confirm live DNS with DNS Lookup and dig.

Example

Typical WHOIS fields

Domain:       example.com
Registrar:    Example Registrar, Inc.
Created:      2018-03-15
Expires:      2026-03-15
Status:       clientTransferProhibited
Nameservers:  ns1.dnsprovider.com

Frequently asked questions

What is the difference between WHOIS and RDAP?

Both provide registration data. RDAP is newer, structured (JSON) and better suited for automated tools.

Can WHOIS show email DNS records?

No. Use MX Lookup and SPF/DKIM/DMARC checkers for mail configuration.

Why is WHOIS contact information hidden?

Privacy protection and registry policies redact personal data in public lookups.

Does WHOIS update instantly after changes?

Registrar updates can take time to appear in public WHOIS/RDAP.

Use these free tools to verify your configuration after applying changes.

WHOIS Lookup Domain Expiry Checker DNS Lookup Domain Health Checker

Need help applying this fix?

Send us your domain, report link or issue details. CheckDomainHealth will review the request and route it to the right technical team if hands-on support is needed.

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