ASN
Autonomous System Number — the identifier of the network that owns an IP range, and a primary classification signal.
An Autonomous System Number identifies a network that controls a block of IP addresses and announces routes for it. Every public address belongs to an autonomous system, and that ownership is public information.
#Why it decides how you are treated
Classification of an address usually starts with its ASN. An address announced by a residential broadband operator is treated as consumer traffic; one announced by a cloud platform is treated as infrastructure. This single lookup is what separates residential from datacenter in practice — not the physical location of the hardware.
#What ASN targeting gives you
Some providers let you select exits by ASN rather than only by country. That is useful when a target behaves differently per carrier, when you need to reproduce a specific network’s view of a service, or when one operator in a country performs noticeably better than the rest.
#Checking an address
Any IP lookup service reports the ASN, usually formatted as AS3320 followed by the operator name. It is the first thing to check when a supposedly residential address behaves as though it were flagged.