ASN Lookup

ASN Lookup - Check ASN Info

ASN WHOIS Lookup tool by DNS Checker helps you find complete ASN info in seconds. You just enter the ASN number and initiate the lookup. The tool quickly shows you:

• ASN block information
• Ownership details
• Contact info
• Absue info
• Routing data, etc. 

What Actually is AS Number Lookup?

AS Number Lookup is a process that helps you find detailed information about an Autonomous System Number (ASN). The primary purpose of performing a WHOIS ASN Lookup is to identify the block owner, location, and routing information. You can easily perform an AS Lookup using our ASN Checker. 

How to Use Our ASN Checker?

Our ASN Checker makes it really easy to perform a WHOIS ASN Lookup. To initiate AS lookup:

1. Enter an ASN number in the input field.

Example input:

• AS24440
• AS15169

2. After you enter the ASN, click the Lookup ASN button. 

The tool will instantly fetch AS WHOIS data from trusted public database registries and display results.

What You See in ASN Whois Results?

The tool displays real WHOIS records in a structured way. The output includes multiple details.

1. ASN Block Information

This section shows the larger ASN range where your ASN belongs.

You may see details like:

• ASN block range 
• Allocation description
• Regional registry, such as 
• African Network Information Center (AFRINIC).
• American Registry for Internet Numbers (ARIN).
• Asia-Pacific Network Information Center (APNIC).
• Latin American and Caribbean Network Information Center (LACNIC).
• Réseaux IP Européens Network Coordination Centre (RIPE NCC).
• Notes about assignments and transfers

2. ASN Ownership Details

This section clearly shows the organization that owns the ASN.

From the sample result:

• Organization Name
• Country Name
• Location

This makes it easy to identify the network owner.

3. Contact and Abuse Information

You also get contact details for network management and abuse reporting.

This includes:

• Admin contact
• Technical contact
• Abuse email address

4. Routing and Maintenance Data

The tool also displays backend network details such as:

• Maintainer records (mnt-by)
• Routing controls (mnt-routes)
• Update history
• Source registry

5. IRT (Incident Response Team) Details

Some ASN records include IRT information.

This section shows:

• Incident response contact
• Validation details
• Abuse handling authority

Use Cases of the ASN WhOIS Lookup Tool

• Network Analysis: Helps you study how networks are structured and managed.
• Cybersecurity: It helps you trace suspicious activity back to its ASN.
• ISP Verification: Confirm the identity of an internet service provider.
• Abuse Reporting: Find the right contact to report network misuse.
• Technical Research: Explore routing and allocation data in detail.

ASN FAQs Answered

What is my ASN number?

Your ASN number is a unique ID that represents your network on the Internet. Usually, internet service providers and large organizations have ASN numbers. If you run a normal home connection, you do not have your own ASN. Instead, your internet service provider (ISP) uses one.

How many types of ASN numbers are there?

There are two main ways to classify ASN numbers:

Based on size:

• 16-bit ASN: Older format. It supports up to 65,536 numbers.
• 32-bit ASN: New format. It supports a much larger number of ASNs.

Based on usage:

• Public ASN: Used on the global internet. Organizations use it to communicate with other networks.
• Private ASN: Used inside private networks. It does not appear on the public internet and is often used for internal routing.

Both types work in a similar way. The difference is in usage and range.

What is an autonomous system in networking?

An Autonomous System, or AS, is a group of IP networks that work under one organization. This system follows a common routing policy. Each AS uses an ASN to communicate with other networks on the Internet.

What type of AS systems require ASN numbers?

Any network that connects with other networks using routing protocols needs an autonomous system number. This includes:

• Internet service providers (ISPs)
• Large companies
• Data centers
• Hosting service provider
• Cloud service providers

Small private networks usually do not need an ASN.

Who assigns autonomous system numbers to Internet registries?

Internet Assigned Numbers Authority assigns ASN ranges to regional registries. Then, regional organizations like ARIN, RIPE NCC, and APNIC distribute ASN numbers to users.

How to find ASN of IP address?

You can find the ASN of an IP address using an IP WHOIS lookup tool. You just enter the IP address, and the tool shows the ASN linked to that IP in front of ‘Origin’ among the results.