Explore notable Autonomous Systems.
An Autonomous System is a collection of IP networks under one administrative authority, identified by an ASN and announcing its prefixes to the global routing table via BGP. This directory covers researched ASNs with their announced prefixes, peer networks, routing data, and organization details.
Corrections welcome — see our editorial policy.
Browse every researched network.
What is an Autonomous System?
An Autonomous System Number (ASN) is a unique identifier assigned to a collection of IP networks under common administrative control. Every major ISP, CDN, cloud provider, university, and large enterprise that connects to the internet has one. When data travels from your device to a website, it crosses several autonomous systems along the way — each hop in a traceroute corresponds to a different ASN boundary.
AS15169 is Google. AS13335 is Cloudflare. AS7922 is Comcast. There are roughly 100,000 active ASNs globally, each announcing the IP prefixes they own to the global routing table via BGP (Border Gateway Protocol).
What does this tool show?
Enter an ASN we've profiled and you'll get a full profile: the organization that holds it, every IPv4 and IPv6 prefix currently announced to the global routing table, registered peer relationships split into upstream (transit providers) and downstream (customer networks), and the IANA block the ASN was assigned from. Each peer ASN is itself a link, so you can walk the routing graph one hop at a time. If you'd rather browse than search, the ASN directory lists every autonomous system we've researched, grouped by what the network is for.
Where does the ASN data come from?
All routing data is sourced from RIPE NCC's RIPEstat service. RIPEstat aggregates from public BGP feeds, the five Regional Internet Registries (ARIN, RIPE NCC, APNIC, LACNIC, AFRINIC), and a number of other authoritative sources. Like all BGP-derived data, prefix and peer lists reflect the routing table at query time and can shift within minutes as the global routing table changes.