What is an ASN?
Networks that exchange routes
An autonomous system is a network or group of networks that presents a routing policy to other networks. Its autonomous system number, or ASN, identifies it in routing information exchanged using BGP.
Reading an ASN lookup
An ASN is commonly written with an AS prefix, such as AS15169. A lookup may show a registered organisation, registry and prefix totals. Registration facts and observed routing are different datasets and can change at different times.
An ASN is not an individual
A large operator can serve many organisations and users. Seeing its ASN associated with an IP address does not identify a subscriber, establish a physical location or prove that traffic is trustworthy.