ASN database

If you're interested in learning more about ASNs and IP address prefixes, check out our ASN database. It offers detailed information on all ASNs, their announced prefixes, peer information, and more. Our database is fully searchable, not only by ASN or prefix, but also by organization name, making it easy to find the information you need.

The tool allows you to

• Look for a specific ASN's
• Search the ASN database using text-search
• Search for announched prefixes using specific IP's or CIDR ranges

The tool will return information on

• Any ASN - all basic information regarding the ASN, such as name, organisation, country and peers
• Any prefix - the basic prefix information itself, info on who is announcing it and so forth

Possible uses of the ASN database

• If you would like to figure out, who is operating a specific IP adress
• If you would like to explore the networks of a specific ASN
• If you need to contact the ASN responsible for a specific IP adress (this includes abuse contacts as well)

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Samples

For a quick introduction, try out these ASN database lookups:
ASN's related to 'amazon.com' ASN's named 'facebook' Lookup of AS7018 Lookup of info on 8.8.8.8

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FAQ

• What is an ASN / Autonomous System Number?
• What are ASN's used for?
• Who assignes the Autonomous System Number?
• What is the 'announhced prefixes'?

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What is an ASN / Autonomous System Number?

The internet is a large collection of small interconnected networks. Each smaller network, is connected to a number of other networks, and thereby creating one large mesh of networks. This is how the internet, as we know it, is build.

Each of these smaller networks is called an Autonomous System (AS), and is identified by an Autonomous System Number (ASN).

Each AS is using the Border Gateway Protocol (BGP) to exchange routing information with other networks on the Internet. The ASN is used by BGP to identify the network that is originating a route and to determine the best path for traffic to take between networks.

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What are ASN's used for?

ASNs are used by BGP to identify the origin of a route and to determine the best path for traffic to take between networks. Each AS is assigned a unique ASN, which is used to identify the AS to other networks on the Internet. BGP uses AS paths, which are sequences of ASNs, to identify the path that traffic takes between networks.

When a network wants to announce a new route, they use BGP to advertise the route to their neighboring networks. The BGP advertisement includes the ASN of the originating network and the IP prefix that is being advertised. When another network receives the advertisement, it adds the ASN of the advertising network to the AS path and uses its own routing policy to determine whether to accept the route or not.

In summary, ASN and BGP are closely related. ASNs are used by BGP to identify the origin of a route and to determine the best path for traffic to take between networks. BGP uses AS paths, which are sequences of ASNs, to identify the path that traffic takes between networks.

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Who assignes the Autonomous System Number?

ASNs are assigned by regional Internet registries (RIRs) such as the American Registry for Internet Numbers (ARIN), the Asia Pacific Network Information Centre (APNIC), the Réseaux IP Européens Network Coordination Centre (RIPE NCC), the Latin American and Caribbean Internet Addresses Registry (LACNIC), and the African Network Information Centre (AFRINIC).

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What is the 'announced prefixes'?

An 'announced prefix' is a range of IP addresses that are assigned to an organization or network (identified as the ASN) for use in routing traffic on the Internet. An ASN that has been allocated an IP address prefix is responsible for announcing that prefix to other networks using the Border Gateway Protocol (BGP). This announcement includes the ASN of the organization and the IP address prefix that is being advertised.

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