IP Tool
ASN Lookup
Lookup autonomous system routing and ownership information using BGP data.
ASN Lookup
Look up details for an Autonomous System Number.
ASN Details
How to Use
Use ASN Lookup in 4 Steps
01
Enter ASN
Type an ASN number like AS13335 or just 13335.
02
Click Lookup
We query BGPView for routing and ownership data.
03
View details
See the network name, country, registry, and prefix counts.
04
Check peers
Review upstream peers to understand routing relationships.
What is an Autonomous System Number (ASN)?
An Autonomous System Number (ASN) is a unique identifier assigned to a collection of IP networks under a single administrative domain that presents a common routing policy to the internet. ISPs, CDNs, cloud providers, and large enterprises each have one or more ASNs.
Major ASN Examples
| ASN | Organization | Registry |
|---|---|---|
| AS13335 | Cloudflare | ARIN |
| AS15169 | Google LLC | ARIN |
| AS16509 | Amazon AWS | ARIN |
| AS8075 | Microsoft | ARIN |
| AS32934 | Facebook (Meta) | ARIN |
| AS20940 | Akamai | ARIN |
Frequently Asked Questions
How do I find the ASN for an IP address?
Use our IP Lookup tool to see the ASN for any IP, or query a BGP looking glass with "show ip bgp <IP>".
What is BGP and how does it relate to ASNs?
BGP (Border Gateway Protocol) is the routing protocol ASNs use to exchange routing information with each other. Each ASN announces its IP prefixes via BGP.
Can an organization have multiple ASNs?
Yes. Large organizations like Google or Amazon operate dozens of ASNs for geographic or administrative separation.
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