Definition
An ASN (Autonomous System Number) is a unique identifier assigned to a network that manages its own routing policy on the internet. ISPs, cloud providers, universities, and large companies each have ASNs. BGP (Border Gateway Protocol) uses ASNs to route traffic between networks. Example: Google's ASN is AS15169, Cloudflare's is AS13335. ASN lookups show which organization owns an IP block.
Use the tool: ASN Lookup — check asn for any domain.