IPv6
Also known as: Internet Protocol version 6, IP version 6, IPng
IPv6, or Internet Protocol version 6, is the newer system for giving every device on the internet an address.
Its addresses are 128 bits long, enough for trillions of addresses for every person on Earth, compared with about 4.3 billion in the older IPv4. While IPv6 was standardized in the 1990s, adoption has been slow because workarounds kept IPv4 alive, and most networks still run both side by side.
IPv6, explained at three levels
At home
Every device on the internet needs an address, like a phone number. The old system is running out of numbers, so IPv6 is a new system with far more of them.
At work
IPv6 lets organizations and providers connect more devices without the cost and complexity of sharing scarce IPv4 addresses.
At home
IPv4 addresses look like 192.168.0.1. IPv6 addresses are longer and use letters and numbers, like 2001:db8::1. Your phone may already use IPv6 without you knowing.
At work
Most networks run 'dual-stack,' supporting both IPv4 and IPv6. IPv6 removes the need for NAT, simplifies end-to-end connections, and includes features like stateless address autoconfiguration. Mobile carriers have led adoption.
At home
Because IPv6 doesn't need NAT, your devices can have public addresses, so the router's firewall becomes even more important. In my opinion, that's a reason to keep router firmware up to date.
At work
Considerations include firewall rules for IPv6 (often forgotten, creating gaps), address planning, logging and monitoring tools that understand IPv6, application compatibility, and the rising cost of buying IPv4 addresses on the transfer market.
Real-world examples
At home
Fatima checked a website that showed her connection details and was surprised to see her phone using an IPv6 address on mobile data, though her old home router used only IPv4.
At work
Marcus manages networks for a Canadian university. Enabling IPv6 across campus reduced reliance on costly IPv4 address purchases, but required updating firewall rules that had only covered IPv4.
How it compares
| feature | IPv6 | IPv4 |
|---|---|---|
| Address length | 128 bits | 32 bits |
| Number of addresses | About 340 undecillion | About 4.3 billion |
| Example | 2001:db8::1 | 192.0.2.1 |
| NAT needed | No | Usually |
IPv6 fixes address scarcity. IPv4 survives on workarounds.
For analysts
If your organization runs IPv6 anywhere, I'd confirm security rules cover it. Firewalls configured only for IPv4 can leave a quiet open path.
History & origin
As the internet grew in the early 1990s, engineers realized IPv4's address supply would run out. The IETF published the first IPv6 specification in 1995, updated in 1998 and finalized as an internet standard in 2017. Meanwhile, network address translation (NAT) let many devices share one IPv4 address, delaying urgency. The global pool of unallocated IPv4 addresses ran out in February 2011, and ARIN, the registry for Canada and the US, exhausted its free pool in 2015. Major websites and providers permanently enabled IPv6 on World IPv6 Launch day, June 6, 2012. Google reported that more than 50 percent of its users reached it over IPv6 for the first time in March 2026, though adoption varies widely by country and provider. In my view, IPv6 is a lesson in how 'good enough' workarounds can delay a better solution for decades.