WHOIS Lookup

WHOIS, and why this tool uses RDAP

WHOIS is the old text protocol registries used to publish who holds a domain or an IP block. Every registry formatted its output differently, it ran on a port browsers cannot reach, and it had no standard way to say a field was withheld for privacy. ICANN has since made the Registration Data Access Protocol (RDAP) the official replacement for generic top-level domains: the same data, as structured JSON over HTTPS.

This tool asks IANA’s bootstrap registry which server is authoritative for the name or address you typed, then queries that registry directly. There is no middleman and no cached copy — you see the registry’s live record, and a link to it.

Reading the result

• Registrar — the company the domain is registered through, with its IANA accreditation number.
• Registered / Expires — expiry turns amber inside 30 days. A domain past its expiry date can usually still be renewed for a while, but it may stop resolving.
• Status codes — EPP codes such as client transfer prohibited are locks, not problems: they stop the domain being moved or changed without the owner’s say-so. Each code is explained in plain English.
• Nameservers — where the domain’s DNS is hosted. Click one to look up its records.
• DNSSEC — whether the registry holds a DS record for the domain.
• Registrant — since GDPR most registrars redact personal contact details. Organisations often remain visible.

For .com and .net the registry holds only the technical record; the registrar keeps the contact details. When the registry points to the registrar’s RDAP server, a button loads that record too.

IP addresses and AS numbers

Enter an IPv4 or IPv6 address and the tool finds which of the five Regional Internet Registries (ARIN, RIPE NCC, APNIC, LACNIC or AFRINIC) allocated it, then shows the network name, the block it belongs to, the organisation it is assigned to, and the abuse contact — the address to report spam or attacks coming from it. AS numbers (for example AS13335) work the same way.

When there is no answer

Some country-code registries, such as .de and .io, do not list an RDAP service with IANA. The tool says so and links to the registry’s IANA entry, which names its own WHOIS service. A not found answer from a registry that does publish RDAP almost always means the domain is not registered.

More free tools

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Last reviewed 2026-10-02. Results come live from the servers named above; DNS Benchmark Pro does not cache, proxy or store them.