Use the most-specific observed route to find an IP address’s BGP origin, then compare that evidence with registry information.
Start with the exact address
Open IP Lookup and enter the IPv4 or IPv6 address. For a practical public lookup, inspect 1.1.1.1. Read the returned snapshot time rather than assuming the answer is current to the second. A private or documentation address receives a local classification instead of an external test.
Why the longest match matters
A more-specific prefix can have a different origin from its covering network. In a hypothetical routing table, an address covered by both a /16 and a /24 uses the /24 for the most-specific origin observation. Looking up only the broader allocation can therefore answer a different question. IPv6 uses the same containment principle with its own prefix lengths.
Follow every reported origin
If multiple AS numbers originate the selected prefix in the available observations, inspect each ASN link. Do not pick the first row and discard the others. Compare collector and snapshot evidence before deciding whether the result is expected.
Separate routing from registration
The registered address holder and the BGP origin are separate fields. A service provider may announce space registered to another organization. Neither field by itself identifies the physical device at an address. Continue through the ASN’s originated prefixes or open the prefix’s path observations. No observed route means this dataset has no matching observation; it is not proof that the address is unused everywhere.