IPv6 was designed to solve IPv4 exhaustion, and its adoption keeps growing. Yet demand for IPv4 addresses remains strong. If you are planning network growth, it helps to understand the difference between the two protocols — and why most businesses still need IPv4.
IPv4 and IPv6 at a glance
- Address size: IPv4 uses 32-bit addresses (about 4.3 billion in total); IPv6 uses 128-bit addresses, an almost unlimited pool.
- Format: IPv4 looks like 203.0.113.10; IPv6 looks like 2001:db8::10.
- Availability: every RIR has exhausted its free IPv4 pool; IPv6 is still readily available from registries.
- Compatibility: the two protocols are not directly compatible — an IPv6-only device cannot talk to an IPv4-only service without translation.
Why IPv4 is still essential
- Much of the internet is still reachable only over IPv4. Many websites, APIs, email servers and enterprise systems have no IPv6 support.
- Customers expect it. Hosting clients, VPN users and enterprise customers frequently require dedicated public IPv4 addresses.
- Dual-stack is the norm. Most networks run IPv4 and IPv6 side by side during the transition, which still needs IPv4 space.
- Translation has costs. Carrier-grade NAT and IPv6-to-IPv4 translation add equipment, complexity and troubleshooting overhead, and can break some applications.
What this means for your business
Deploying IPv6 is a smart long-term investment, but it does not remove the need for IPv4 in the near term. Most growing networks need a plan for both: IPv6 for scale and future-proofing, and enough IPv4 to stay reachable by every user and service.
If you need more IPv4, you can buy IPv4 addresses as a long-term asset or lease IPv4 for flexibility. And if your transition to IPv6 frees up space, you can sell your unused IPv4 block.
Frequently asked questions
IPv6 adoption is increasing, but the two will coexist for many years. Most networks currently run both protocols (dual-stack).
IPv4 has only about 4.3 billion addresses, and the rapid growth of internet-connected devices and services used up the free pools held by the Regional Internet Registries.