Classify any IPv4 address as private, public, loopback, link-local, CGNAT, multicast or reserved.
Classification is a range test on the first two octets. Anything that falls outside every reserved block is globally routable space assigned by a regional internet registry. Knowing whether an address is RFC 1918, CGNAT or public determines whether a flow needs NAT, whether it can be filtered at the edge, and whether it may legally appear in the global routing table.
Private/Public IP
The address is matched against the reserved ranges 10/8, 172.16/12, 192.168/16, 127/8, 169.254/16, 100.64/10, 224/4 and 240/4.
The address is matched against the reserved ranges 10/8, 172.16/12, 192.168/16, 127/8, 169.254/16, 100.64/10, 224/4 and 240/4. Classification is a range test on the first two octets. Anything that falls outside every reserved block is globally routable space assigned by a regional internet registry.
Knowing whether an address is RFC 1918, CGNAT or public determines whether a flow needs NAT, whether it can be filtered at the edge, and whether it may legally appear in the global routing table.
This calculator takes 1 input: IPv4 address. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.