Understanding ASN Lookup
When you connect to the internet, your IP address belongs to a wider network operated under a single routing policy. That network is identified by an Autonomous System Number (ASN). Our ASN lookup reveals who operates the network behind an IP and shows context that helps with routing diagnostics, abuse triage, and performance testing. It works for both IPv4 and IPv6 and is designed to be fast, simple, and privacy-conscious.
What This Tool Shows
Paste any valid IP and you’ll see the ASN (for example, AS15169), the AS name (such as Google LLC), and the ISP or organization attributed to that range. Where available from our routing datasets, we also surface the most specific announced prefix and the Regional Internet Registry (RIR) that allocated the block (ARIN, RIPE NCC, APNIC, LACNIC, or AFRINIC). If hostname resolution is part of your check, switch to our DNS lookup without leaving the flow.
How It Works
After validating the format of the IP (IPv4 or IPv6), we query upstream IP intelligence and parse the ASN string. Many providers expose the value as a single field like “AS12345 Example Corp.” We normalize that into two clear attributes: ASN = AS12345 and AS Name = Example Corp. If only a number is present (e.g., “12345”), we safely prefix it as “AS12345.” Because routing changes over time (and anycast can return different nodes), results may vary; for quick geographic context, you can run a quick check on the IP geolocation map.
Practical Uses & Tips
Engineers use ASN data to understand path selection and peering issues, SOC teams enrich logs during incident response, and content teams tune allow/deny policies. If latency is high, the ASN can hint at the transit provider involved; for abuse cases, identifying the operator simplifies escalation. When you need to identify a site’s address in context, the website IP finder helps, and you can confirm your own address on what is my IP address. To explore everything else, see all tools.