Routing GuideWhat is an ASN?
An Autonomous System Number identifies a network that announces routes on the internet, such as an ISP, cloud provider, university or large company.
Why ASN matters
The internet is made of many independently operated networks. Each autonomous system controls routing for its own IP ranges and exchanges route information with other networks. ASN data helps identify which organization is responsible for an IP address and how traffic may be routed.
For example, a home connection may show the ASN of a telecom provider, a cloud server may show the ASN of a hosting company, and a VPN may show the ASN of the VPN provider or the data center it uses.
How ASN helps troubleshooting
ASN can help explain why a service sees your traffic as residential, mobile, hosting, proxy or VPN. It can also be useful when investigating routing issues, blocked networks, suspicious traffic, CDN behavior or regional access differences. ASN does not identify a person, but it gives strong context about the network path.