// METHODOLOGY

IP Lookup

How an arbitrary IPv4 or IPv6 address is geolocated, and how accurate each field actually is.

// What is tested

That the input is a syntactically valid IPv4 or IPv6 address. Anything else is rejected before any lookup runs.
That the address is publicly routable. Private, loopback, link-local and reserved ranges are rejected, because they have no meaningful location and exist on every network at once.
Country, region and city for the address, plus the ISP or hosting provider and the ASN announcing it.
The reverse DNS (PTR) hostname, when published.

IP2Location: Commercial IP geolocation database. Its foundation is the Regional Internet Registry allocation records — ARIN, RIPE NCC, APNIC, LACNIC and AFRINIC — refined with routing data, reverse-DNS naming patterns and latency measurement.
DNS over HTTPS: Cloudflare with Google Public DNS as fallback, for the PTR lookup.

Registry allocation is recorded fact. City-level placement is inference, which is why independent geolocation services disagree about the same address without either being wrong.
Country accuracy is high. City accuracy is commonly quoted by vendors at 50–80% within 50km, and is materially worse for mobile, satellite, VPN and corporate-backhaul addresses.
An address cannot be tied to an individual or a street address. That requires subscriber records held only by the ISP, obtainable only through legal process.
The ASN and ISP fields are considerably more stable than the location fields, and usually more informative.

Last reviewed against the code on 2 August 2026.