ASN Lookup
Look up BGP Autonomous System Numbers. Enter an IP address or ASN to get routing info, organization, announced prefixes, and network details.
What Is an ASN?
An Autonomous System Number (ASN) is a globally unique identifier assigned to a network — or a group of networks — under a single administrative domain. ASNs are assigned by Regional Internet Registries (RIRs) like ARIN, RIPE, APNIC, LACNIC, and AFRINIC.
Every major internet provider, cloud platform, and large enterprise has its own ASN. Google is AS15169, Cloudflare is AS13335, AWS is AS16509. When you trace a route across the internet, you're traversing multiple ASNs.
Common Uses for ASN Lookup
- Identify which company owns an IP address or range
- Investigate suspicious traffic sources
- BGP route analysis and troubleshooting
- Network security and threat intelligence
- Verify CDN or hosting provider for a domain
- Geolocation and IP intelligence research
Frequently Asked Questions
An Autonomous System Number (ASN) is a unique number assigned to a network under a single routing policy. ASNs are used in BGP to identify which organization controls a block of IP addresses on the global internet.
BGP (Border Gateway Protocol) is the routing protocol that interconnects autonomous systems on the internet. It determines the best path for data packets to travel between networks worldwide.
Enter any IP address above. The tool queries BGP routing tables and RDAP databases to identify the ASN that announced the IP prefix containing that address.