IP WHOIS Lookup

What an IP WHOIS lookup tells you

An IP WHOIS lookup answers one question: who is this IP address registered to? Every public IPv4 and IPv6 address belongs to a block that a Regional Internet Registry (RIR) has allocated to an organisation — an ISP, a hosting company, a university, a large business. This tool reads that record live over RDAP (the modern, JSON replacement for the old WHOIS protocol) from the RIR responsible for the address, and shows:

• Organisation — the entity the block is registered to.
• Network name and CIDR range — e.g. 8.8.8.0/24, the span of addresses in the same allocation.
• Allocation type — direct allocation, reassignment, and so on.
• Country of registration.
• Abuse contact — the email to report spam, scanning, or attacks coming from the address.
• Registration and last-changed dates.
• ASN — the autonomous system that routes the address on the internet.

It does not reveal a person's name or street address. Registry records identify the network operator, not the individual using a given address at a given moment.

WHOIS is not geolocation

Many tools labelled “WHOIS” actually return geolocation — an estimated city and ISP from a commercial database. That is a different thing. WHOIS/RDAP is the authoritative registry record of who holds the block; geolocation is a best guess at where a device on that block might be. This tool returns the registry data. For the full explanation, see WHOIS and geolocation are not the same lookup.

Common uses

• Reporting abuse. Found scanning or spam from an IP in your logs? The abuse contact here is where the report goes.
• Identifying a host or CDN. Check whether an address belongs to AWS, Google, Cloudflare, a hosting reseller, or a residential ISP.
• Checking an ASN. Tie an address to its autonomous system to understand who routes it.
• Due diligence. Confirm that a service is hosted where its operator claims.
• Network troubleshooting. See the size of an allocation (the CIDR) and the operator to contact.

Which registry answers

Five RIRs divide the world; RDAP automatically routes your query to the right one.

RIR	Region
ARIN	United States, Canada, parts of the Caribbean
RIPE NCC	Europe, Middle East, Central Asia
APNIC	Asia-Pacific
LACNIC	Latin America and the Caribbean
AFRINIC	Africa

How this tool works

Enter an IP (or leave it blank to check your own) and the server makes one HTTPS RDAP request to the responsible registry, parses it, and adds an approximate geolocation from a separate provider for context. Nothing is sent to a third party from your browser, and the address you look up is not written to any log or database. Results are cached in memory for a short time so repeated lookups are fast.