What Is an ASN Lookup?
ASN LookupOverview of ASN Lookup
An ASN (Autonomous System Number) lookup involves querying a database or API to retrieve information about a specific ASN. This process shows details such as the organization that owns and operates the network, the country where the organization is based, and the range of IP address prefixes (blocks of IP addresses) associated with that ASN.
Why ASN Lookup Is Important
Performing an ASN lookup provides valuable context for various networking and security-related tasks. For network engineers, it helps with understanding peering relationships between networks and optimizing network performance. Security professionals use ASN lookups to identify the origin of network traffic, investigate malicious activity emanating from specific networks, and implement targeted security policies.
How to Perform an ASN Lookup Using IPinfo
IPinfo offers several ways to perform an ASN lookup — through our API, database download, or web interface. We return information including the ASN's organization name, domain, type, and abuse details.
Links to Related Documentation and Tooling
- Hosted Domains by ASNs Report
- ASN API Developer Resource
- IP to ASN Database Developer Resource
- IP Data Types Developer Resource
Additional Resources
- Blog: IPinfo CLI: Lookup IP or ASN details
- Community Post: ASN Explained
- FAQ: Why Some IP Addresses Don't Have ASN Data