Regional Internet registry

A Regional Internet Registry (RIR) is a regional organization entrusted with the management and allocation of Internet resources. Its responsibilities include the management of IP addresses (IPv4 and IPv6) and AS numbers.

There are currently five active regional registries worldwide:

• Réseaux IP Européens Network Coordination Centre (RIPE NCC)
• American Registry for Internet Numbers (ARIN)
• Asia-Pacific Network Information Centre (APNIC)
• Latin American and Caribbean Internet Addresses Registry (LACNIC)
• African Network Information Centre (AfriNIC)

Each of these regional registrars is allocated IP address ranges by IANA. Blocks are taken from these and assigned to Local Internet Registries (LIRs), which in turn serve the end customer. LIRs are mostly Internet service providers.

The Number Resource Organization (NRO) was established in 2003 through the signing of a reciprocal agreement to protect common interests and coordinate cooperation. In coordination with ICANN, the NRO acts as the Address Supporting Organization (ASO) within the ICANN structures.