Tools /
Engineering & scale
/ Vol III
IP Assignment Lookup
Enter an IPv4 or IPv6 address. Get back the address type (RFC 1918 private, CGN, link-local, documentation, multicast, ULA, ...), which Regional Internet Registry holds the parent block (ARIN, RIPE NCC, APNIC, LACNIC, AFRINIC), and one-click deep-links to that RIR's WHOIS — plus a BGP looking-glass for AS / route details. The lookup itself runs in your browser; clicking an external link is the only thing that leaves the page.
Everything runs in your browser. No automatic network requests — external WHOIS / looking-glass links are explicit and open in a new tab so you decide when to share the address.
Result
—
Awaiting input
Type or paste an IP address above.
Address
RIR assignment
External lookups
These open in a new tab and send the address to the named service. None fire automatically.
How IP assignment works
IANA → RIR → LIR → end user
IANA holds the master IPv4 / IPv6 allocation tables. It delegates large blocks to the five RIRs; each RIR re-allocates to Local Internet Registries (typically ISPs and large enterprises); LIRs assign sub-blocks to end users. This tool stops at the RIR level — that's the static information that fits client-side. The country and org are an RIR WHOIS query away.
The five RIRs
ARIN — North America (US, Canada). RIPE NCC — Europe, Middle East, parts of Central Asia. APNIC — Asia-Pacific. LACNIC — Latin America & Caribbean. AFRINIC — Africa. Plus a sixth, IANA-direct, for special-purpose blocks (RFC 1918, loopback, multicast, documentation, etc.).
IPv4 is fragmented by /8
Of 256 IPv4 /8s, roughly 100 are held by ARIN (US-heavy legacy plus modern allocations), 50 by RIPE, 50 by APNIC, 10 by LACNIC, and 6 by AFRINIC — the rest are special-purpose (RFC 1918, loopback, RFC 5737 documentation, multicast, future-reserved). The lookup table here is the IANA ipv4-address-space.xml registry as of 2026.
IPv6 is cleaner — RIR per /12
Current IPv6 allocations are tidy: ARIN gets 2600::/12, APNIC gets 2400::/12, LACNIC gets 2800::/12, RIPE gets 2A00::/12, AFRINIC gets 2C00::/12. The older 2001::/16 block was carved in /23 chunks across all five RIRs in 1999–2005; the lookup still resolves those correctly.
Why country isn't built in
Mapping IP → country requires either a freshly-updated ~5–20MB geolocation database (MaxMind, IPinfo, etc.) or a public API call. The first makes the page heavy and the freshness story messy; the second breaks the everything-runs-in-your-browser promise the rest of these tools make. The compromise: the external-lookup buttons above open public WHOIS / BGP services in a new tab — you decide when to share the address.
Hurricane Electric BGP toolkit
bgp.he.net is the de-facto free BGP looking glass — for any address it surfaces the announcing AS, the route prefix in the global table, peering, and the registered country. Always linked from this tool's External lookups for both v4 and v6.
Don't confuse RIR with country
A /8 held by ARIN isn't necessarily routed in the US. ARIN-issued space is used worldwide; a US-based multinational with operations in São Paulo will route ARIN-held addresses there. Use the WHOIS link to find the registered org and country — the RIR alone only tells you which registry processes the paperwork.
Special-purpose blocks short-circuit RIR lookup
If the address is RFC 1918 private, RFC 6598 CGN, loopback, link-local, RFC 5737 documentation, multicast, or reserved, there is no RIR assignment — IANA holds those blocks for protocol use. The tool flags these and skips the WHOIS deep-links.