Real BGP data, not a geolocation guess

An "IP to organization" lookup can mean two very different things: geolocation databases that estimate a physical location from historical and inferred data, or genuine routing-table lookups that report which network actually announces that address block on the internet right now. This tool does the latter — it queries Team Cymru's DNS-based whois service, which reflects the real, current BGP announcement data collected from internet routing infrastructure. That distinction matters because BGP data answers "who controls the network this address belongs to" reliably and precisely, while geolocation is inherently an estimate that can be stale or simply wrong, especially for cloud and CDN address ranges that don't map cleanly to a single physical location.

Why one IP can show multiple ASN rows

A single IP address can genuinely fall within more than one announced BGP prefix simultaneously — a large network might announce both a broad aggregate block and a more specific sub-block carved out of it, for traffic engineering or multi-homing reasons, and both announcements can technically cover the same address. Rather than arbitrarily picking one to show, this tool lists every matching announcement it finds, since which one actually carries traffic to that address in practice depends on real-time BGP path selection that isn't knowable from a static lookup — showing all matches is more honest than guessing which one "wins."

Why private and non-routed addresses return nothing

ASN and BGP announcements exist only for addresses that are actually routed on the public internet — private address ranges (RFC 1918), loopback, and other non-routed blocks are, by definition, never announced via BGP because they're not supposed to be reachable from the public internet at all. A private IP returning no ASN results isn't this tool failing to find data; there genuinely is no BGP announcement to find, since that address was never meant to appear in global routing tables in the first place.