What is ASN (Autonomous System Number)?
Also: autonomous system number
An ASN, or autonomous system number, identifies a network that controls a block of IP addresses and announces routes for them on the internet (for example AS13335 is Cloudflare). ASNs reveal who owns an IP — an ISP, a hosting company, a VPN provider — which is central to classifying it.
Every public IP is announced by an autonomous system. Mapping an IP to its ASN tells you whether it belongs to a residential ISP, a datacenter, a CDN, a mobile carrier, or a known VPN operator — the first and most reliable layer of IP classification.
ASN ownership can change, and some networks mix residential and hosting traffic, so ASN data is combined with other signals rather than used alone.
How IPLogs handles it
IPLogs resolves ASN ownership from MaxMind GeoLite2, PeeringDB, and Team Cymru, and classifies each ASN as residential ISP, datacenter, CDN, carrier, or VPN operator.
ASN lookup