OWNERSHIP & ROUTING
ASN Lookup
Use RIPEstat to map IP addresses to routed prefixes and inspect autonomous-system details.
39DExternal testRuns from the toolbox server
RUN TEST
ASN Lookup
HOW IT WORKS
About the ASN Lookup
Autonomous systems exchange internet routes using BGP. The lookup combines prefix-to-origin information with the public AS overview data observed by RIPE NCC systems.
How to use this result
- Run the test from this server.Use a public hostname, address, prefix or ASN in the format requested above.
- Compare with another observation point.Run a local command or use a second provider to identify location-specific behaviour.
- Correlate related evidence.Use the related tools below to compare DNS, routes, ports, TLS and application responses.
- Keep the time and context.Routing, DNS caches and reputation data change, so record when the result was collected.
Common interpretation issues
- An IP can be covered by more than one route, with the most-specific route normally winning.
- The network operator and the website owner may be different organisations.
- Private AS numbers are not globally visible.
NEED HELP INTERPRETING THE RESULT?
39D supports business networks, cyber security and managed IT.
For ongoing support or a larger infrastructure project, speak to the 39D team.
Frequently asked questions
What is an ASN?
It is a number identifying a routing domain that presents a common policy to other networks.
Is the origin always the final host provider?
Not necessarily; transit, anycast, DDoS protection and delegated infrastructure can affect the visible origin.