What is RIR?

An RIR (Regional Internet Registry) is one of five organisations that allocate IP addresses and AS numbers to networks in their part of the world.

The five RIRs are AFRINIC (Africa), APNIC (Asia-Pacific, including Australia), ARIN (Canada, the United States and parts of the Caribbean), LACNIC (Latin America and parts of the Caribbean) and the RIPE NCC (Europe, the Middle East and parts of Central Asia). They receive large blocks from IANA and allocate from them to their members: ISPs, hosting companies, universities, enterprises and, in some regions, National or Local Internet Registries that pass addresses on to their own customers. Each RIR is a membership organisation with policies developed through open community processes, which is why the rules for, say, getting the last remaining IPv4 space or transferring addresses differ between regions. Alongside allocation, RIRs run services the internet depends on: whois and RDAP databases recording who holds each block, delegation of reverse DNS for their address space, and RPKI trust anchors so holders can sign ROAs.

Engineers deal with their RIR when they need their own address space or a public ASN, for example to multi-home with two providers. Day to day, they meet RIR data while looking up who owns an address in a log, creating ROAs in the RIR portal, or maintaining route objects. Some RIRs also run an IRR, and these can tie route objects to the registry's record of who holds the address space, which some third-party IRRs cannot. A common confusion is thinking addresses come straight from IANA, or that an ISP owns the addresses it lends to customers: holdership is recorded at the RIR. The IRR, RPSL and AS-SETs lesson shows how RIR databases and routing registries fit together.