Regional Internet Registries are the organizations responsible for allocating IP addresses and Autonomous System Numbers across the globe. Understanding how they work is useful for anyone managing infrastructure, requesting IP space, or thinking about internet routing.
Publish date: 5/22/2026
If you've ever tried to get a block of IP addresses for your network, you've probably run into the term "Regional Internet Registry," or RIR. They're easy to overlook, but these organizations sit at the very foundation of how the internet is organized. Without them, the addressing system that keeps packets flowing to the right places simply wouldn't work.
Whether you're a network engineer, a sysadmin spinning up infrastructure, or just someone curious about how IP addresses are handed out, understanding RIRs gives you a clearer picture of the internet as a system, not just a service you plug into.
The internet runs on addresses. Every device that communicates online needs a unique IP address, and someone has to be responsible for making sure those addresses are handed out in an orderly, non-overlapping way.
That responsibility ultimately sits with IANA, the Internet Assigned Numbers Authority, which is operated by ICANN. IANA manages the global pool of IP address space, but it doesn't deal directly with individual organizations or networks. Instead, it delegates large blocks of addresses to a tier of regional bodies: the Regional Internet Registries.
From there, RIRs distribute address space to Local Internet Registries (LIRs), such as ISPs and hosting providers, who then allocate it further to their customers or use it internally.
Think of it as a hierarchy: IANA at the top, RIRs in the middle, and LIRs and end users at the bottom.
There are five RIRs in total, each serving a specific part of the world.
ARIN (American Registry for Internet Numbers) covers the United States, Canada, and many parts of the Caribbean. It's one of the older registries and manages a large portion of the IPv4 space that was allocated during the early commercial internet era.
RIPE NCC serves Europe, the Middle East, and parts of Central Asia. RIPE is short for Réseaux IP Européens, and its NCC (Network Coordination Centre) is headquartered in Amsterdam. It's also one of the most active registries in terms of policy development.
APNIC covers the Asia-Pacific region, which includes a massive and fast-growing portion of the world's internet users. Given the size of that footprint, APNIC was actually the first RIR to exhaust its IPv4 free pool, back in 2011.
LACNIC handles Latin America and the Caribbean (the parts not covered by ARIN). It's headquartered in Montevideo, Uruguay.
AFRINIC manages IP resources for Africa. It's the newest of the five RIRs, having been founded in 2004, and it still holds some of the remaining IPv4 address space in the global pool, though allocations continue to tighten.
RIRs don't just hand out IPv4 and IPv6 addresses. They manage a few key internet resources:
IPv4 address blocks. These are the classic 32-bit addresses (like 192.0.2.0) that most people picture when they think of an IP address. The global free pool of IPv4 space is largely exhausted, which has pushed organizations to either transfer addresses, move to IPv6, or use both.
IPv6 address blocks. IPv6 uses 128-bit addresses, which gives an astronomically larger pool. RIRs actively encourage and facilitate IPv6 adoption, and getting IPv6 space is generally much more straightforward than fighting over legacy IPv4 blocks.
Autonomous System Numbers (ASNs). An ASN is a unique identifier assigned to a network that runs the Border Gateway Protocol (BGP). If you want to announce your own IP prefixes on the internet, you'll need an ASN. Networks with ASNs are called Autonomous Systems, and BGP is how they exchange routing information with each other. If you're interested in a deeper look at how that works, you'll want to read this article.
WHOIS and route registry data. RIRs maintain public databases where you can look up who holds a given IP range or ASN. This is useful for troubleshooting, abuse reporting, and verifying route origins. The RIPE Database and ARIN's WHOIS tool are commonly used examples.
The path from the global pool to your server rack follows a fairly consistent process.
IANA allocates large blocks, typically /8s or similar, to RIRs. The RIR then breaks those down and allocates smaller chunks to LIRs, which are usually ISPs or hosting providers who are members of the registry. Those LIRs can then either use the addresses themselves or sub-allocate them to their customers.
When a business or operator wants address space directly from an RIR, they typically need to justify their request with documentation showing current usage and projected need. The specific policies vary between registries, but most require that you demonstrate you have a plan for the address space rather than just sitting on it.
For most companies, the practical path is to work with a provider that's already an LIR and can either assign addresses from their own allocation or help sponsor a direct assignment from the RIR.
IPv4 exhaustion is one of the most significant practical consequences of how IP addressing has developed. With only about 4.3 billion possible IPv4 addresses, and the internet growing far beyond what its designers anticipated, regional free pools started running dry starting around 2011.
Today, most RIRs operate under what's called "final /8 policy" or similar restrictions, meaning they can only issue very small allocations from whatever remains. ARIN, for example, moved to its IPv4 Waiting List for new requests, where applicants wait for returned or revoked space to become available.
This scarcity has driven a secondary market for IPv4 transfers, where organizations that hold address blocks they no longer need can sell or transfer them to others, subject to each RIR's transfer policies. Prices for IPv4 space have risen significantly over the past decade as a result.
IPv6 is the long-term answer to this, and RIRs have made it progressively easier to get IPv6 allocations. The challenge has been adoption, since getting IPv6 space is one thing; getting every network, device, and application in the ecosystem to support it is another.
If you're at the point where you need your own address space or want to run your own ASN, here's a general picture of how that works.
Working through an LIR. For most organizations, the simplest path is working with an ISP or hosting provider that's already an LIR member of the relevant RIR. They can sponsor a PI (Provider Independent) assignment, which means the addresses are assigned to you and don't disappear if you change providers.
Becoming an LIR. Larger organizations, especially those managing multiple networks or operating at scale, sometimes apply to become LIRs themselves. This requires becoming a member of the relevant RIR, paying annual fees, and agreeing to their policies. In return, you get a direct allocation and more flexibility in how you distribute and use the space.
Getting an ASN. If you want to run BGP and announce your own prefixes, you'll need an ASN. Applications go through your regional RIR and typically require that you have at least two BGP peers and a legitimate reason to operate an Autonomous System. The process varies by registry but isn't particularly complicated for qualifying networks.
IP transfers. If you need IPv4 space quickly and can't wait, the transfer market is an option. RIRs have defined transfer policies that allow address blocks to move between organizations, sometimes within the same region, sometimes across regions. This usually involves a broker and can be expensive depending on the size of the block.
For companies running internet infrastructure, being an LIR or working closely with one has real operational implications. Provider Independent (PI) space means your addresses are yours regardless of which upstream provider carries your traffic. That matters a lot for multihoming, where you're connected to multiple transit providers for redundancy, and for portability if you change providers.
Having your own ASN also lets you participate directly in the routing ecosystem, giving you more control over how your traffic is routed and making it easier to implement things like BGP communities or traffic engineering policies.
For organizations with significant traffic or complex routing requirements, these aren't just technical details; they directly affect performance, resilience, and cost.
An RIR is a policy and administrative body that allocates internet resources like IP addresses and ASNs to networks within its region. An ISP is a commercial company that provides internet connectivity to customers. ISPs often become LIR members of an RIR so they can receive address allocations and assign them to their customers.
It's possible, but most small organizations work through an ISP or hosting provider instead. Getting space directly from an RIR typically requires becoming a member, paying fees, and meeting minimum size thresholds. For most use cases, working through a provider is simpler and more cost-effective.
A WHOIS lookup queries a registry's database to find out who is responsible for a given IP address or domain. RIRs maintain these databases for the IP space and ASNs they manage. They're commonly used for network troubleshooting and abuse reporting.
Yes, the free pool of unallocated IPv4 space at the global IANA level was exhausted in 2011. Regional pools have followed suit at different times since then. IPv4 addresses are still available through transfers on the secondary market, but they come at a cost. IPv6 adoption is the long-term path forward.
Provider Independent (PI) space is assigned directly to your organization, meaning it belongs to you regardless of which ISPs or providers carry your traffic. This is in contrast to Provider Aggregatable (PA) space, which comes from your ISP's allocation and would typically need to be returned if you change providers.
Each RIR develops its own policies through a community-driven process, so there are differences between them. However, they all operate within the broader framework set by IANA and ICANN, and they coordinate through a group called the Number Resource Organization (NRO).
An IP address block is a range of addresses used to identify devices on the internet. An ASN (Autonomous System Number) is a unique identifier for a network that uses BGP to exchange routing information. You need an ASN if you want to announce your own IP prefixes to other networks, but having IP addresses doesn't automatically mean you need an ASN.
Regional Internet Registries are an often-overlooked but foundational part of how the internet operates. They're the organizations that make sure IP address space and routing identifiers are distributed in a way that keeps the global network functioning, and understanding how they work is genuinely useful if you're managing any kind of infrastructure at scale.
Whether you're thinking about getting your own IP space, running BGP, or just want to understand how your provider's addresses are sourced, the RIR system is worth knowing.
At xTom, we operate as a registered LIR with allocations from multiple RIRs, which means we can offer IP transit with real network depth, alongside dedicated servers, colocation, and scalable NVMe KVM VPS through V.PS. We also offer shared hosting for simpler workloads, and you can see the full range of what we do at our services page.
Ready to talk infrastructure? Get in touch with our team and let's find the right setup for your network.