What Is IPv4 and How Are IPv4 Addresses Allocated?
IPv4 is the addressing protocol that identifies devices on most of today's Internet, using 32-bit addresses such as 192.0.2.1. Because only about 4.3 billion addresses exist, the global pool was exhausted years ago, and new addresses now come mainly through transfers or from the remaining reserves held by regional Internet registries (RIRs). If you are an organization in Africa needing address space, you apply to AFRINIC, the RIR responsible for allocating and managing Internet numbers (IPv4, IPv6 and ASNs) across the region.
What IPv4 actually is
IPv4 (Internet Protocol version 4) is the network-layer protocol that gives every connected interface a numeric address so packets can be routed between networks. It has been the default addressing system of the Internet since the early 1980s.
An IPv4 address is 32 bits long, written as four decimal numbers separated by dots:
192.0.2.1— a single host address198.51.100.0/24— a block (prefix) of 256 addresses203.0.113.0/22— a larger block of 1,024 addresses
The /24 and /22 notation is a prefix length: it says how many leading bits are fixed for the network. The remaining bits identify hosts inside it. This is the same structure you configure on routers, firewalls and servers.
Why the address pool ran out
32 bits give a theoretical maximum of 2^32 addresses — roughly 4.29 billion. That seemed ample in the 1980s, but the growth of the web, mobile devices, cloud computing and always-on connections consumed the space far faster than expected.
The result is IPv4 exhaustion: the central pool of unallocated addresses was depleted, and RIRs can no longer hand out large fresh blocks on demand. In practice this means:
- New entrants often receive small allocations rather than large ones.
- Address space is increasingly obtained through transfers between organizations.
- Networks rely more heavily on NAT (network address translation) to share a single public address among many devices.
- Accurate registration of who holds which addresses becomes more important, because the resource is scarce.
How IPv4 addresses are allocated
Internet number resources are distributed through a hierarchy:
- IANA (the Internet Assigned Numbers Authority) manages the global pools and distributes them to the five RIRs.
- RIRs allocate addresses to organizations in their region. AFRINIC is the RIR for Africa, and its stated responsibility is the allocation and management of Internet numbers — IPv4, IPv6 and ASNs — in that region.
- Members and stakeholders (ISPs, enterprises, institutions) receive blocks and register how they are used.
AFRINIC's services cover registry services, policy participation, learning and community activity in one place. Its published member-facing tools include a membership registration portal, IPv6 resource management, a name system anycast programme, and participation in the Policy Development Process — the mechanism through which the community shapes how Internet resources are managed.
The policy layer
Allocation is not purely administrative. The rules for how addresses are requested, justified and returned are set through the Policy Development Process, where the community debates and approves changes. AFRINIC's own blog describes this as "Africa's Internet policy table," noting that every resource member has a seat — a contributor account describes moving from feeling like an outsider to taking part in policy discussions at an AFRINIC meeting.
If you want to influence allocation rules in the region, that process is the route, not a support ticket.
IPv4 vs IPv6: when to consider transitioning
IPv6 uses 128-bit addresses, which removes the exhaustion problem for the foreseeable future. The two protocols can run side by side.
| Dimension | IPv4 | IPv6 |
|---|---|---|
| Address size | 32-bit | 128-bit |
| Typical notation | 192.0.2.1 |
2001:db8::1 |
| Availability of new space | Scarce; transfers and small allocations | Large allocations generally available |
| Coexistence | Runs alongside IPv6 | Runs alongside IPv4 (dual stack) |
When to consider moving:
- New network build-outs — deploy dual stack from the start rather than retrofitting later.
- Growth constrained by IPv4 scarcity — if you cannot obtain enough IPv4 space, IPv6 restores headroom.
- Long-lived infrastructure — equipment and services expected to run for years should support IPv6 now.
- Existing IPv4-only estates — transition can be gradual; keep IPv4 running while adding IPv6.
AFRINIC lists IPv6 resources as a distinct service area, reflecting that IPv6 management is now a standard part of registry work rather than an optional extra.
Practical starting points
If your goal is to understand or obtain IPv4 in the African region:
- Review AFRINIC's registry and membership services to see what applies to your organization.
- Check the Policy Development Process pages if you need to know the current rules for requesting or transferring resources.
- Use the member registration portal if you are joining as a member.
- Plan for IPv6 in parallel, since new growth increasingly depends on it.
The key takeaway: IPv4 still carries most traffic, but its address pool is finite and effectively exhausted. Allocation now happens through RIRs like AFRINIC, governed by community-set policy, with IPv6 as the long-term answer to address scarcity.