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ASN Lookup

Autonomous system number lookup for network owner details, BGP ASN context, IP prefixes, registration and peer relationships.

Examples AS15169 AS13335 AS36459
Guide

How ASN lookup works

Enter an ASN such as AS15169 or 15169 to run an autonomous system number lookup. The result page shows network owner details, RIR registration, abuse contact, IPv4 and IPv6 prefix counts, sample CIDR blocks and peer context when available.

ASN lookup is useful when you need to identify who operates an IP network, find IP prefixes by ASN, compare hosting providers, or understand which organization appears behind a public IP address.

FAQ

Frequently asked questions

What is an Autonomous System Number (ASN)?

An Autonomous System Number, or ASN, is a globally unique identifier for a network operator that controls one or more IP prefixes and exchanges routing information with other networks using BGP. Examples include AS15169 for Google and AS13335 for Cloudflare.

What does an ASN lookup show?

An ASN lookup shows the network owner, organization, RIR, registration details, country, abuse contact, IPv4 and IPv6 prefix counts, sample announced prefixes, and observed peer or upstream relationships when available.

How do I find IP prefixes by ASN?

Enter an ASN such as AS15169 or 15169. The prefix table lists sample IPv4 and IPv6 CIDR blocks associated with that autonomous system, plus counts that help estimate the network size.

What is the difference between a peer and an upstream?

An upstream, also called a transit provider, carries traffic to the wider internet. A peer exchanges traffic directly, often at an internet exchange. Both relationships help explain how an AS connects to other networks.

Is this real-time BGP monitoring?

No. This ASN lookup summarizes routing and registration datasets available to the tool. It is useful for network owner lookup, prefix discovery, and routing context, but not a replacement for real-time BGP monitoring or outage detection.