ASN Lookup
Find the autonomous system number, organization, ISP and network details associated with an IP address.
What is an ASN lookup?
An ASN lookup identifies the autonomous system associated with an IP address. An autonomous system is a network or group of networks operated under a common routing policy and identified on the internet by an Autonomous System Number, or ASN.
Large internet service providers, cloud platforms, hosting companies, universities and enterprise networks often operate their own autonomous systems. Looking up the ASN behind an IP address helps reveal which organization is responsible for announcing that network to the global routing system.
How to use the ASN Lookup tool
- Enter a valid IPv4 or IPv6 address.
- Run the ASN lookup.
- Review the ASN, organization, ISP and network location information returned for the address.
What ASN lookup results mean
The ASN identifies the autonomous system that originates or manages the route containing the IP address. The organization field normally identifies the network operator, while the ISP field may identify the service provider associated with the connection.
ASN ownership does not necessarily identify the end user of an IP address. A cloud server, VPN endpoint, corporate gateway or residential customer may all use addresses announced by a larger provider’s autonomous system.
Common uses for ASN information
- Identify the network operator behind an IP address.
- Investigate traffic seen in server, firewall or application logs.
- Distinguish residential, hosting and cloud network infrastructure.
- Compare IP addresses that belong to the same autonomous system.
- Add network ownership context to security or abuse investigations.