01
Pick one public resource
The same field accepts an IPv4 address, IPv6 address, AS13335, or 13335. A domain, CIDR range, private address, or whole log is intentionally rejected before any network request.
IP & Networks
ASN lookup
Enter one public IPv4 or IPv6 address, or an AS number. Query only when you choose to send it.
ASN lookup
Public IP or ASN
Lookup result
Enter a public IP or ASN to begin.
A lookup sends your entered public IP or ASN directly from this browser to O-X-L and RDAP.org / the responsible registry. Nothing is sent until you run a lookup.
Enter a public IP or ASN to begin.
ASN lookup helps when a log contains an unfamiliar address and you need to identify the network announcing it. A registration range and a routed prefix can differ: one describes allocation, the other describes a BGP observation.
Use this ASN lookup to keep those records side by side. It shows the response source and retrieval time instead of turning a registered country or organisation into a claim about someone's physical location.
Why use this ASN lookup
Read routing observations and registry records without mixing their meanings.
A routed prefix is not a registration range
For an IP to ASN lookup, the page matches the address against prefixes announced by its reported AS. The matching BGP prefix is labelled separately from the IP block in the RIR RDAP record. They can have different boundaries and names.
A record carries its own source and time
ASN lookup displays the final RIR response host, its registration and last-change events, plus when this browser retrieved the answer. The routing database publishes a daily update cadence, not an exact timestamp for this particular prefix.
Check what each result can actually tell you
02
Send the query deliberately
Examples only fill the field. Look up or Ctrl/Cmd + Enter sends the current value to the public sources; editing it later immediately disables export until a fresh response arrives.
03
Compare the two sources
Read the observed prefix and AS name as routing data, then inspect the separate RDAP allocation record. Expand raw RDAP to verify the registry's exact fields; missing fields remain marked unavailable.
Network attribution with visible evidence
IP to ASN lookup
A public IP can lead to an origin AS and the longest matching observed prefix. Prefix matching happens in this browser against O-X-L's ASN list, rather than treating the RIR allocation as the announced route.
Autonomous system lookup
An AS number opens its IPv4 and IPv6 announced-prefix lists. The page shows 50 at a time, but Copy JSON and Download JSON carry the complete returned list.
Raw registry evidence
The responsible RIR's RDAP response is available as raw JSON. Its handle, registered name, range, registration event and last-change event remain distinct from routing-source fields.
What the records do and do not establish
- One public input per request
- Only a single public IPv4/IPv6 address or AS number is accepted. ASN lookup does not resolve domains, upload files, query CIDR blocks in bulk or discover your current address. Private and documentation IP ranges stop locally.
- Origin is not an identity
- An origin ASN or registered organisation cannot identify an individual, residence or exact device location. Country fields in registration data, if present in raw RDAP, refer to registry context rather than a precise geolocation.
- Sources can disagree or fail
- O-X-L route observations and RIR RDAP registrations are independent. If either source fails, available evidence remains visible with a partial-result warning; absent prefixes or dates are never filled from a different field.
- Time labels are specific
- Retrieved at means when this browser received the response. RDAP last changed means the registration object's event date. The route provider states daily database updates but does not expose a per-prefix update timestamp.
ASN lookup questions
Is ASN lookup free?
Yes. This page has no account or API key. Public O-X-L and RDAP services may impose their own request limits, so a 429 response asks you to retry later.
Where does the data come from?
Routing ASN and prefix lists come from O-X-L's public BGP-derived database. Registration details and the raw record come through RDAP.org from the responsible Regional Internet Registry. Each result shows the actual source URL.
How fresh are the results?
O-X-L says its database updates daily but gives no exact per-prefix timestamp. The page labels the browser retrieval time and any RDAP registration or last-change event separately; neither is a promise of live routing.
Can I run this from the command line?
This page is a browser tool and does not provide a command-line client or API endpoint. For scripts, use the data providers' documented APIs directly and respect their limits.
What is the difference between IP to ASN lookup and IP WHOIS lookup?
IP to ASN lookup concerns the network observed announcing a prefix. IP WHOIS or RDAP concerns the address block's registration. The owner name and the origin AS can legitimately differ.
Have another network attribution case?
Run an ASN lookup with both sources in view
Enter one public IP or AS number, review the origin and registration separately, then export the sourced result.