Finding ASNs in bulk with an API
To find the ASN for many IPs at once, use an API instead of one-by-one lookups. Abstract's IP Intelligence API returns the ASN, its type, the operator's domain, and risk flags for any IP in a single request. For the mechanics of resolving an IP to its ASN, see IP-to-ASN mapping.
ASN lookup vs WHOIS
An ASN lookup tells you which network currently routes an IP. WHOIS tells you who registered a domain or IP block. For traffic analysis and risk scoring, the routing answer is what you want. To find your own network's ASN, see what is my ASN.
Frequently Asked Questions
How do I find the ASN of an IP address?
Enter the IP into an ASN lookup tool. It returns the ASN, the organization that operates it, the ASN type, and the operator's domain in one step.
Can I find an IP's ASN for free?
Yes. Abstract's ASN Lookup tool is free and needs no signup, and the IP Intelligence API has a free tier for programmatic lookups.
What does the ASN of an IP tell me?
It identifies the network operator behind the address, such as an ISP, hosting provider, or data center, which is a strong signal for fraud detection and traffic analysis.
How do I find the ASN for many IPs at once?
Use an API. The IP Intelligence API returns the ASN for any IP in a single request, so you can map large lists without manual lookups.
Is an ASN lookup the same as WHOIS?
No. An ASN lookup shows which network routes the IP right now; WHOIS shows registration records for a domain or IP block. They answer different questions.
