IPv4 vs IPv6 — What's the Difference?
IPv4 uses 32-bit addresses (like 192.168.1.1), providing about 4.3 billion unique addresses; IPv6 uses 128-bit addresses (like 2001:0db8::1), providing a vastly larger address space designed to outlast IPv4's exhaustion.
Published October 4, 2026
IPv4 uses 32-bit addresses (like 192.168.1.1), providing about 4.3 billion unique addresses; IPv6 uses 128-bit addresses (like 2001:0db8::1), providing a vastly larger address space designed to outlast IPv4's exhaustion.
Why they differ
- IPv4's limited address space has been effectively exhausted for years, worked around with techniques like NAT (Network Address Translation)
- IPv6 was designed specifically to solve this scarcity with an astronomically larger address pool, plus some built-in security and routing improvements
How to choose
- Most networks today run both protocols simultaneously ("dual-stack") during the long transition period
- Application developers rarely need to handle the difference directly, since most networking libraries and servers support both transparently
FAQ
Why hasn't IPv6 fully replaced IPv4 yet?
The transition requires updating enormous amounts of existing infrastructure, and NAT extended IPv4's usable lifetime enough that the pressure to fully migrate has been gradual rather than urgent.