IPv4 vs IPv6: What's the difference?
IPv4 and IPv6 are network-layer addressing protocols. IPv6 provides a vastly larger address space and modernizes several parts of IP networking.
IPv4
IPv4 uses 32-bit addresses and remains widely deployed, often together with private addressing and NAT.
IPv6
IPv6 uses 128-bit addresses, supports a huge address space and is designed for end-to-end IP connectivity without depending on NAT.
Key differences between IPv4 and IPv6
| Decision factor | IPv4 | IPv6 |
|---|---|---|
| Address size | 32-bit addressing with about 4.3 billion total addresses. | 128-bit addressing with an extremely large address space. |
| Common deployment | Often relies on private addressing and NAT because public space is scarce. | Designed for extensive end-to-end addressing; NAT is not a core requirement. |
| Neighbour and configuration | Uses ARP and can use DHCPv4. | Uses Neighbor Discovery and supports SLAAC and/or DHCPv6 depending on design. |
Choose IPv4 if
Choose IPv4 where legacy compatibility or an existing IPv4-only environment requires it.
Choose IPv6 if
Deploy IPv6 when your providers, applications and security controls support it, ideally in a planned dual-stack transition.
Practical example
A company may keep IPv4 for legacy applications while enabling IPv6 for modern Internet and cloud services. Clients receive both address families and select the usable path. Security teams must then monitor and filter both stacks, because disabling attention to IPv6 does not guarantee that IPv6 traffic is absent.
Can you use IPv4 and IPv6 together?
Dual stack is the most common migration model: devices run IPv4 and IPv6 at the same time. This avoids a disruptive flag day and lets services move gradually. Translation technologies also exist, but they add design and troubleshooting complexity and should be chosen intentionally.
Common mistake to avoid
A frequent mistake is enabling IPv6 without equivalent firewall, DNS
Key takeaway
IPv6 is the long-term protocol, but most organizations still need a controlled coexistence strategy with IPv4.
Frequently asked questions
Does IPv6 make NAT unnecessary?
IPv6 provides enough address space for globally unique addressing, so address conservation through NAT is not required. Firewalls are still required for policy and security.
Should I disable IPv4 when enabling IPv6?
Usually not during migration. Most organizations run dual stack until application, provider and operational dependencies are ready for an IPv6-only design.
Is IPv6 automatically more secure?
No. It supports modern protocol features, but security still depends on correct firewalling, patching, segmentation, monitoring and configuration.