What an ASN lookup shows
An autonomous system is a network or group of networks under one routing policy. An ASN lookup converts a number such as AS15169 into useful context: the network holder, registry source, and a sample of announced IP prefixes. This is helpful for log analysis, allow-list review, abuse triage, and understanding whether an IP belongs to an ISP, VPN, cloud provider, or enterprise network.
How ASN data connects to IP geolocation
IP geolocation tells you where an address is likely routed, while ASN data tells you who announces the route. A VPN exit, cloud server, mobile carrier, or home ISP can each have different ASN patterns. For a single address, start with IP address lookup, then follow the ASN here for broader routing context.
Related checks
Use the WebRTC leak test to see what your browser exposes, the IPv6 test to compare IPv4 and IPv6 reachability, and the MAC address lookup for local-network hardware address details.
Frequently asked questions
What is an ASN?
An ASN, or Autonomous System Number, identifies a network that announces routes on the internet, such as an ISP, cloud provider, university, or large company.
What does ASN lookup show?
ASN lookup can show the autonomous system holder, registry data, and announced IP prefixes associated with that network.
How is ASN related to IP lookup?
IP lookup often returns the ASN behind an address. ASN lookup then expands that number into network ownership and routing context.