How IP Addresses Work
What Is IPv6 and Why Do We Need It?
IPv6 is the internet's answer to running out of addresses. Its supply is so vast that we will effectively never exhaust it.
The address shortage
IPv4 offers about 4.3 billion addresses. That sounded limitless in the 1980s, but a world of smartphones, laptops, servers, and smart devices blew past it. By the 2010s, the regional registries had handed out their last big blocks. The internet needed far more room.
A staggering amount of space
IPv6 uses 128-bit addresses instead of IPv4's 32-bit ones. That yields roughly 340 undecillion addresses — a 39-digit number. It is enough to give every grain of sand on Earth its own address many times over. Address exhaustion, the problem that motivated IPv6, simply ceases to exist.
What an IPv6 address looks like
IPv6 addresses are written in hexadecimal, in eight groups separated by colons: 2001:0db8:0000:0000:0000:8a2e:0370:7334. Long runs of zeros can be compressed with a double colon, shortening that to 2001:db8::8a2e:370:7334.
More than just more addresses
IPv6 also modernized the protocol. It simplifies parts of the packet header for faster routing, builds in features that IPv4 bolted on later, and allows devices to configure their own addresses automatically. Because every device can have a real public address, IPv6 reduces the need for Network Address Translation.
The slow switchover
IPv4 and IPv6 are not directly compatible, so the internet runs both at once during a long transition. Many connections are "dual-stack," holding an IPv4 and an IPv6 address simultaneously — which is why a tool like IP Ducky can show you both. Adoption keeps climbing, but IPv4 will remain in service for years to come.