WhatIP tool
Look up the organization behind an autonomous system number, or find the ASN for an IP address.
Example:
Results will appear here.
What you should know
An Autonomous System Number (ASN) identifies a distinct network on the internet -- typically an internet service provider, a cloud platform, a university, or a large company's own network -- that controls how traffic for its block of IP addresses is routed. Every public IP address belongs to exactly one ASN at a time, which makes the ASN a more precise way to identify a network than the company name alone.
You can search either by AS number directly (for example AS15169) or by an IP address, in which case this tool resolves the ASN that address currently belongs to. Results include the network's registered name, its country, and -- where available -- the size of the IP address block it announces.
ASN data is widely used in network security to distinguish traffic from known cloud/hosting providers versus residential ISPs, in network engineering to understand internet routing, and in research to map how the internet is structured at a large scale.