What Is a RIR? Regional Internet Registry Roles
A regional internet registry (RIR) registers and distributes IP address space and AS numbers for its service region. There are five RIRs. For an existing prefix, the authoritative registry record determines where to start; the address’s apparent location does not.
Find the responsible registry
| RIR | Service region | Operator reference |
|---|---|---|
| RIPE NCC | Europe, the Middle East and parts of Central Asia | RIPE resource rules |
| ARIN | United States, Canada and parts of the Caribbean and North Atlantic | ARIN requirements |
| APNIC | Asia Pacific | APNIC requirements |
| LACNIC | Latin America and parts of the Caribbean | LACNIC requirements |
| AFRINIC | Africa | AFRINIC requirements |
The Caribbean is split between service regions. Use the registry’s country list for a new organization and a WHOIS or RDAP referral for an existing block. A prefix can move between compatible RIRs, so neither its first octet nor an old allocation list reliably identifies its current registry.
The NRO’s RIR directory is the official overview of the five registries and their regions.
What the registry establishes
The RIR records the organization responsible for a resource, its contacts and relevant resource status. It processes allocations, assignments and approved changes of holder. It also provides services such as reverse DNS delegation and resource certification, subject to the account and resource’s eligibility.
For an operator, this means the registry is the place to resolve an outdated holder name, recover authorized account access, apply for resources or establish whether a proposed transfer is allowed.
Allocation and assignment describe different responsibilities. See RIR versus LIR before choosing a direct account or a provider relationship.
What a registry record does not establish
| Evidence | What it answers | What it does not prove |
|---|---|---|
| RIR registration | Who is registered and which registry administers the resource | That a particular seller is authorized to sign today |
| ROA | Which origin ASN is authorized under RPKI | That a route is currently visible everywhere |
| BGP observation | Which network announces a prefix from that vantage point | That the announcing network is the registered holder |
| Geolocation database | Where a vendor believes an address is used | The resource’s registry or contractual status |
An abuse contact can investigate activity from a network. The RIR does not operate that network, filter its traffic or guarantee a prefix’s reputation.
Choose the correct request
- New resources: establish the appropriate account and meet the applicable allocation or assignment policy. Membership alone does not guarantee IPv4 availability.
- Existing resources with stale records: establish authority over the registered entity before requesting changes.
- A new holder: use the applicable transfer or corporate-change procedure. Editing a contact object is not a transfer.
When an acquisition needs registry coordination, IPv4 transaction support should begin with eligibility and the holder of record. Commercial agreement and registry approval are separate milestones.