An Autonomous System Number (ASN) identifies a network on the internet, such as a hosting provider, an ISP, or a large company. Each AS holds a set of IP address blocks.

What does ASN Lookup show?

Enter an AS number, like AS13335, to see the organization name, how many IPv4 and IPv6 networks the AS holds, its total IPv4 addresses, and the list of network prefixes.

Can I search by company name?

Yes. Type an organization name, like cloudflare, to list the AS numbers whose names contain it. Select an AS number to see its networks.

How do I find the ASN of a domain or an IP address?

Use IP Lookup. It shows the ASN and organization for any IP address or domain.

Yes, with a daily limit shared with IP Lookup. Sign up for a free account to get more, and see pricing for higher limits.

ASN Lookup

Find the organization and IP networks behind any AS number

AS203898

Cloudflare Inc

IPv4 networks

IPv6 networks

256

IPv4 addresses

Networks 3

185.122.0.0/24 2606:54c1:a::/48 2606:54c1:c::/48

Data Source: This product includes GeoLite2 Data created by MaxMind, available from maxmind.com.