BGP ASN Lookup

Look up an Autonomous System Number or an IP and see the holder, country, announced IPv4/IPv6 prefixes, and BGP peer neighbors. Live data from the RIPEstat API.

About BGP & ASNs

The public internet is a network of autonomous systems — independent networks operated by ISPs, hosting providers, universities, and large enterprises. Each AS is identified by a globally unique ASN assigned by a Regional Internet Registry (ARIN, RIPE, APNIC, LACNIC, or AFRINIC). They exchange reachability information using BGP (Border Gateway Protocol), the routing protocol that holds the internet together.

This tool queries the RIPEstat Data API, which aggregates the global BGP table from RIS (Routing Information Service) collectors plus WHOIS data from the five RIRs. You can look up either:

Common Use Cases

Frequently Asked Questions

An Autonomous System Number (ASN) is a globally unique 16- or 32-bit integer assigned to an organization that operates one or more IP networks under a single, clearly defined external routing policy. ASNs are assigned by the Regional Internet Registries (ARIN, RIPE, APNIC, LACNIC, AFRINIC) and used by BGP — the protocol that exchanges routes between networks on the public internet.
All lookups use the RIPEstat Data API, which aggregates BGP routing data from RIS (Routing Information Service) collectors worldwide plus WHOIS data from the five Regional Internet Registries. It updates every few hours.
Either the IP is in a reserved/bogon range (RFC 1918 private space, multicast, documentation), or it is unannounced (the prefix isn't currently in the global BGP table). Both are common.
ASNs were originally 16-bit (0–65535). The space ran out, so RFC 6793 extended them to 32 bits. Modern allocations are 32-bit; you'll see values like AS213000 or higher. AS23456 ("AS_TRANS") is reserved as a placeholder for 32-bit ASNs in legacy 16-bit-only routers.
No. Your browser calls the RIPEstat API directly. Their privacy policy applies to the request; we don't proxy or log it.
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