Look up an Autonomous System (BGP) by AS number. Pass asn as AS3333 or 3333. Returns the AS holder/operator name, the IANA/RIR allocation block it falls in, whether it is currently announced, and a live routing-status block: first/last seen prefixes, announced IPv4/IPv6 prefix + address counts, RIS peer visibility, and observed BGP neighbour count. Data: RIPEstat (RIPE NCC), free and public. Distinct from geo.ip (host geolocation) and dns/whois (name lookups) — this is who-owns-and-routes-this-AS, observed live from the global routing table. For network forensics, abuse/security triage, and infrastructure mapping.