IANA and the RIRs: Who Hands Out IP Addresses
IP addresses are not handed out at random — there is a clear hierarchy of authority.
The Hierarchy
IANA (ICANN)
└─ RIR (5 regional registries)
└─ LIR / ISP
└─ End user / organization
IANA holds the global pool and delegates large blocks to the five RIRs, which allocate to ISPs (LIRs), which assign to customers.
The Five RIRs
| RIR | Region |
|---|---|
| ARIN | North America |
| RIPE NCC | Europe, Middle East, Central Asia |
| APNIC | Asia-Pacific |
| LACNIC | Latin America & Caribbean |
| AFRINIC | Africa |
When you run the IP Lookup tool, the "RIR" field tells you which registry manages that address, and the network/organization come from its RDAP database.
This same system ran out of free IPv4 blocks — see IPv4 exhaustion.