A regional internet registry (RIR) is a nonprofit organization that allocates and keeps the official records for IP addresses and autonomous system numbers (ASNs) in one region of the world. There are five: ARIN, RIPE NCC, APNIC, LACNIC and AFRINIC. They receive large blocks of address space from the global body that coordinates numbering and hand out smaller blocks to internet providers, enterprises and other organizations under policies developed by their regional communities. For a business, the RIR is where you go to hold your own IP addresses or ASN, and its records are what other networks check to confirm you hold them.
At a glance
- Five RIRs cover the world, each serving a defined region.
- They allocate IPv4 and IPv6 address blocks and ASNs, and maintain public registration records.
- Policies are set through open regional community processes, so rules and fees differ by registry.
- New IPv4 space is very limited in most regions; IPv6 is generally easy to obtain.
- RIRs also run services used for routing security, such as RPKI.
What problem it solves
Networks connected to the internet need public addresses that no one else is using, and they need a way to prove which addresses it holds. Someone has to keep that list. RIRs are the regional record keepers: they make sure each block is assigned to one holder and publish who holds what.
For businesses, this matters most when they want addresses that are their own. Addresses assigned by an internet service provider usually belong to the provider and must be returned when the contract ends, forcing a renumbering project. Holding address space and an ASN through an RIR lets an organization keep its addresses across provider changes and announce them to several providers at once with BGP, which is the basis of multi-provider failover.
How it works
The hierarchy. A global coordinating function allocates large blocks to the five RIRs. Each RIR allocates or assigns smaller blocks to its members. In some regions, national internet registries (NIRs) or local internet registries (LIRs), often ISPs, sit between the RIR and end users and pass on space.
Getting resources. An organization applies to its RIR, directly or through a sponsoring member depending on the region, and shows that it meets the policy for the resource it wants. Requests for an ASN or IPv6 block are usually routine. IPv4 is a different story: with free pools largely exhausted, most regions run waiting lists or tightly limited allocations.
Transfers. Because new IPv4 is scarce, much of it changes hands through transfers between holders. RIRs record approved transfers, and each has its own transfer policy, including rules for transfers between regions and after mergers.
Registration data. RIRs publish registration records, often looked up through WHOIS or RDAP services, showing who holds a block and how to contact them. Keeping that information current matters for abuse handling and for proving control during a transfer or dispute.
Routing security. RIRs operate the trust anchors for Resource Public Key Infrastructure (RPKI), which lets holders publish which networks are authorized to announce their addresses.
For help sourcing or managing address space, see our IPv4 and IPv6 Addresses solution page.
When it matters for buyers
- Multi-provider internet. Running BGP with two providers usually requires your own addresses and ASN, or the provider’s permission to announce theirs.
- Changing providers. Your own address space avoids renumbering firewalls, VPNs and allow-lists elsewhere.
- Mergers and acquisitions. Address blocks held by an acquired company need to be transferred under RIR policy and registration updated.
- Needing more IPv4. If the RIR cannot supply it, the choice is usually between buying, leasing or moving more services to IPv6.
- Routing security requirements. Some providers and customers expect address holders to publish RPKI records.
Questions to ask vendors
- Are the addresses you assign to us provider-assigned, and what happens to them if we leave?
- Will you announce our provider-independent addresses and ASN, and do you validate them against RIR and RPKI records?
- Can you help us apply for addresses or an ASN, or sponsor our request where the region requires it?
- If we lease or buy IPv4, how will the RIR registration be handled and who holds the records?
- Who will keep our registration contact details and RPKI records current?
How it differs from IP address leasing
An RIR is the registry that allocates address space and records who holds it. IP address leasing is a commercial arrangement in which an existing holder rents some of its addresses to another organization for a fee. Leased addresses usually stay registered to the holder, and the lessee gets authorization to use and announce them under the terms of the lease. Similarly, addresses from your IP transit or internet provider are registered to that provider, not to you. Resources registered to your organization through the RIR are what give you independent control.