ASN Lookup

An Autonomous System (AS) is a network that controls its own routing on the internet, such as an ISP, cloud provider or large company. Enter an ASN (like AS15169) or an IP address.

Tool status: Uses an external service Relies on a third-party API that may be rate-limited or temporarily unavailable.

What this tool can and cannot do

Registration data comes directly from the responsible Regional Internet Registry (ARIN, RIPE NCC, APNIC, LACNIC or AFRINIC) over RDAP. For an IP address, the ASN is taken from the free IPinfo Lite database. Live routing data (announced prefixes) is not shown: the free source for it (RIPEstat) does not allow commercial use without written permission.

Data sources: RDAP (regional internet registries) · IPinfo Lite (IP → ASN)

Understanding the results

“Registered to” is the organisation holding the AS number. The abuse contact is where to report spam or attacks coming from this network.

Troubleshooting

  • "Not registered": the number has not been assigned by any registry, or it is a private-use ASN (64512–65534, 4200000000–4294967294).

Frequently asked questions

What is an ASN used for?

ASNs are used by the Border Gateway Protocol (BGP), the system networks use to exchange routes. Each AS announces the address ranges it is responsible for.