ASN WHOIS Lookup
Find autonomous system registration information.
An autonomous system number identifies a network that announces its own routes on the internet — a provider, a hosting company or a large organisation. An ASN lookup returns the registry record for that number: the operator, its country and its contacts.
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How ASN WHOIS Lookup works
What it does
Find autonomous system registration information.
What you get
Autonomous system registration and allocation details.
Live data sources
The target is sent to a network provider. Results include their source; timeouts and unavailable data are clearly marked.
What if a check cannot finish?
Confirm your input and try again. A timeout, blocked request, or unavailable provider is not proof that a domain is broken. Internet measurements and third-party services have limits.
ASN WHOIS Lookup — frequently asked questions
What is an autonomous system?
A set of IP prefixes under one routing policy, announced to the rest of the internet with BGP. Every provider of any size operates at least one.
How do I find the ASN for an IP address?
Use the IP WHOIS lookup — the registry record for an address block names the autonomous system that announces it.
Why would I look up an ASN?
To identify who really operates the network behind an address, to investigate abuse across a provider's whole range, or to understand routing and peering relationships.