IP Address Lookup — ASN, prefix, registry and allocation
Resolve any IPv4 or IPv6 address to the autonomous system announcing it, the exact BGP prefix, the responsible registry and the original allocation date.
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Lookups resolve live through the Team Cymru IP-to-ASN mapping service over DNS-over-HTTPS. Results reflect current BGP announcements rather than a cached commercial database, which is why the prefix shown is the real announced route and not a marketing approximation. Country here is the registry country of the allocation, not a city-level geolocation guess.
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Frequently asked
Why is there no city in the result?
Because there is no honest city. Registry data gives you the country an allocation was issued in. City-level geolocation is a commercial inference from latency, user reports and ISP hints, and it is wrong often enough that we do not present it as fact for arbitrary addresses.
What is the prefix field?
The exact CIDR block currently announced in the global routing table that contains this address. It tells you how large a chunk the operator routes as one unit.
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