ASN / BGP Lookup

Lookup ASN ownership and BGP routing context by ASN, IP, or prefix
This free online asn / bgp lookup runs in your browser and is part of our Developer Tools collection.

ASN / BGP Lookup

Lookup ASN ownership and routing context by ASN, IP address, or CIDR prefix.

What this helps with

  • Identify network ownership and upstream ASN context
  • Map public IPs to their origin ASN quickly
  • Learn how prefixes relate to BGP routing entities
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Instant In-Browser Execution Runs locally in JavaScript without wait times or server delays.
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100% Privacy & Security Your inputs and files are never stored or logged on remote servers.
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Cross-Device Responsive Fully optimized for mobile smartphones, tablets, and desktop displays.
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100% Free Forever No subscription fees, no signups, and no software installations.

How to Use the Online ASN / BGP Lookup

1 Enter ASN, IP Address, or Prefix

Type an Autonomous System Number (e.g. `AS15169` or `15169`), an IP address, or CIDR prefix.

2 Query BGP Routing Database

Click "Lookup ASN" to retrieve registration and Border Gateway Protocol (BGP) routing records.

3 Inspect Organization & Routing Data

Review Network Name, Organization, Country, Allocated IPv4 and IPv6 Prefix count, and Regional Internet Registry (RIR).

4 Examine BGP Prefixes

Browse the complete list of IP address prefixes routed and announced by this autonomous system.

Frequently Asked Questions

Common questions about using this free online asn / bgp lookup.

What is an Autonomous System Number (ASN)? ▾
An ASN is a globally unique identifier assigned by IANA/RIRs to a large network (like an ISP, cloud provider, or university) that controls its own unified routing policy using the Border Gateway Protocol (BGP).
What are examples of well-known ASNs? ▾
`AS15169` (Google LLC), `AS13335` (Cloudflare), `AS16509` (Amazon.com / AWS), `AS32934` (Meta / Facebook), and `AS8075` (Microsoft Corporation).
What are the 5 Regional Internet Registries (RIRs)? ▾
ARIN (North America), RIPE NCC (Europe & Middle East), APNIC (Asia-Pacific), LACNIC (Latin America & Caribbean), and AFRINIC (Africa).
How does ASN lookup help with cybersecurity? ▾
Security analysts use ASN lookups to identify who owns an attacking IP, evaluate whether incoming web traffic originates from residential ISPs or cloud hosting proxies, and block malicious autonomous networks in firewalls.

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