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

12 ASes matching "cloudflare"

ASN	Organization	IPv4 networks	IPv6 networks	IPv4 addresses
AS22061	Cloudflare,	1	1	256
AS402542	Cloudflare,	1	1	256
AS13335	Cloudflare, Inc.	1,008	1,650	1,409,536
AS14789	Cloudflare, Inc.	214	216	67,584
AS132892	Cloudflare, Inc.	19	21	28,928
AS139242	Cloudflare Sydney, LLC	0	2	0
AS202623	Cloudflare Inc	10	13	30,464
AS203898	Cloudflare Inc	1	2	256
AS209242	Cloudflare London, LLC	233	21	97,024
AS394536	Cloudflare, Inc.	0	1	0
AS395747	Cloudflare, Inc.	18	19	4,864
AS400095	Cloudflare, Inc.	1	1	256

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