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ASN Lookup

Instantly find the Autonomous System Number (ASN), underlying organization (ISP), and IP routing prefixes for any given IP address.

💡 How to Use This Tool

Evaluating an IP address to find out its Autonomous System Number (ASN) and managing organization is simple. Follow these steps:

1

Enter IP Address

Type or paste any IPv4 or IPv6 address into the search box above. By default, it detects and displays your current IP address.

2

Click Lookup

Click the "Lookup ASN" button. The tool queries our securely hosted local MaxMind database immediately.

3

Review Details

Instantly review the owning Autonomous System Number (ASN), the specific organizational entity (ISP), and routing Network block.

📖 About ASN Lookup

What is the ASN Lookup Tool?

This tool allows you to find the Autonomous System Number (ASN), the managing organization (ISP), and network blocks associated with any IPv4 or IPv6 address. It reliably queries the MaxMind GeoLite2 ASN database locally to provide completely offline, highly accurate lookup results.

Use Cases

  • Network Operations: Map problematic IP ranges directly to their Autonomous System to handle routing efficiency and latency.
  • Security & Fraud Analysis: Cross-reference IPs against known datacenters, VPN operators, or specific Autonomous System Numbers for abuse detection.
  • Troubleshooting: Identify routing loops or bottlenecks by checking the exact network block and ASN an IP routes through.

Key Features

ASN Identification

Look up the Autonomous System Number an IP address belongs to in milliseconds.

Provider Details

Identify the ISP or organization that manages the IP space associated with your request.

BGP Routing Prefix

View the specific IP subnet block (CIDR prefix) being routed for the requested IP address.

Privacy & Security

Your privacy is absolutely fundamental. All IP address searches are performed securely and directly on our servers using a local GeoIP database. We do not transmit the IP addresses you search for to any external tracking or monitoring APIs. No logs are kept of the user queries.

❓ Frequently Asked Questions

An Autonomous System Number (ASN) is a globally unique identifier assigned to a network or group of networks (an Autonomous System) that share a common routing policy. It is essential for routing traffic across the Internet via the Border Gateway Protocol (BGP).
Finding an ASN helps in network troubleshooting, identifying the owner of an IP block (such as a specific ISP, datacenter, or VPN provider), optimizing routing paths, and preventing fraud or abuse by blocking traffic from specific undesirable networks.
Yes, we utilize the industry-standard MaxMind GeoLite2 ASN database. This database is regularly updated to provide highly accurate information about IP to ASN assignments globally.
Absolutely. All IP lookups are performed securely and directly on our servers without relying on third-party APIs. We do not log or track the IP addresses you search for, ensuring complete privacy.

Version History

1.0.0

Initial release of ASN Lookup tool

Mar 01, 2026