What the heck happened to IPv6?

IPv6 was supposed to change everything. It was the future of the internet. A massive upgrade to address IP address shortages, simplify networks, and make everything faster and more secure. Yet here we are, decades later, still clinging to IPv4.

So, what happened to IPv6, and why are we still so dependent on IPv4?

What are IPv4 and IPv6?

Every internet-connected device needs an IP address

In short, every device connected to the internet needs what’s known as an IP address (Internet Protocol address). It’s a unique identifier that tells other devices where to send data, and you can think of it like a postal address, but for your phone, laptop, or router.

Basically, when you visit a website, your device sends a request to a server’s IP address, and that server sends information back to your device. Without IP addresses, data wouldn’t know where to go, and the web (as we know it) wouldn’t work.

So, IP stands for Internet Protocol, while “v4” and “v6” indicate the version. IPv4 is the format the internet has used for decades, but is running out of room (more on this in a moment), and IPv6 is its successor, designed to expand the available address space and fix many of IPv4’s old limitations.

Why IPv6 was the dream

Modern fixes for the modern internet

It may surprise you to know that for a while, the internet was running out of room. The original IPv4 standard used a 32-bit format, which has a limit of around 4.3 billion unique addresses. Now, that understandably sounded like plenty in the 1980s, but once smartphones, laptops, routers, and even smart fridges came online, the pool started drying up fast. In 2015, there was serious concern that IPv4 addresses would completely run out.

That’s where IPv6 comes in. IPv6 addresses use a 128-bit format, which means there is effectively an unlimited number of addresses: roughly 340 undecillion (that’s 340 followed by 36 zeros). So, yeah, a ridiculous number.

However, IPv6 wasn’t just about increasing the address space. It also introduced other changes, such as automatic device configurations, stronger encryption, advanced routing protocols, and more.

The IPv6 rollout was insanely slow to begin with

You can’t just flip a switch

Although IPv6 promised to deliver more address space (and did!), the transition to IPv6 has been slow going. There are a few reasons for this, but it largely revolves around cost and compatibility.

To start with, IPv4 and IPv6 can’t talk to each other directly. There is no single switch to flip to enable compatibility and the migration of the entire internet. No, that would be too easy. Instead, every ISP, data center, website, and router had to update or replace hardware and software to handle both systems, in a setup known as dual-stack networking.

The idea was that dual-stack networking would enable the transition from IPv4 to IPv6 to become a gradual process, with providers, ISPs, and so on to upgrade over time. However, the reality was different, and dual-stack networking turned out to be expensive, still required extensive hardware upgrades and configuration changes, and could be complicated to implement.

Furthermore, in some cases, companies just didn’t see the point in upgrading, especially during the earlier years when IPv4 was running just fine. For the overwhelming majority of people, the difference between IPv4 and IPv6 isn’t a consideration, and if people aren’t complaining, why fix something that technically isn’t broken?

For years, IPv6 adoption hovered in the single digits. Some ISPs and enterprise networks stayed IPv4-only because there was no immediate benefit to switching. And since most devices could share one IPv4 address via NAT (Network Address Translation), the pressure to move to IPv6 was delayed even further.

You’re probably using IPv6 without realizing

Uptake is higher than ever

Here’s the thing: despite how it seemed, IPv6 didn’t go anywhere. The transition to IPv6 had to happen whether network companies liked it or not. The IPv4 address pool really was diminishing rapidly, and the solution was already there.

And now, according to Google’s IPv6 adoption statistics, nearly 45 percent of users globally connect using IPv6, with mobile networking leading the charge. Many carriers in the U.S., Europe, and Asia now use IPv6 by default. Your phone is probably using it right now, even if you’ve never heard of it.

Furthermore, the major networks and tech companies, like Google, Meta, Microsoft, Netflix, and Cloudflare, have been IPv6-ready for years at this point.

IPv6 is everywhere, but invisible

You’re using it, but you have no idea

That means that really, the IPv6 internet already exists, and you’re already using it. You just can’t tell, and that means the transition is happening nearly seamlessly.

If you’re on a reasonably modern phone, broadband connection, or cloud platform, there’s a good chance you’ve already been using IPv6. It’s running quietly in the background, managed automatically by your router, your ISP, or your mobile carrier.

Because of dual-stack networking, most users never know which protocol they’re on. The transition has been happening gradually—and invisibly—for years.

The result is strange: we’re simultaneously living in the old and new internet. IPv4 is the legacy system we can’t shake, while IPv6 is the quiet successor that nobody talks about because it just works.

IPv6 didn’t fail

IPv4 isn’t going away any time soon

IPv4 isn’t going anywhere soon. It’s far too entrenched in legacy systems, old hardware, and industrial infrastructure. Businesses still run critical equipment designed only for IPv4. And since NAT and address trading keep it functional, there’s no existential threat forcing a sudden switch.

Then there are the companies and organizations sitting on old IPv4 blocks, which are now worth millions. These rare, unused IPv4 address blocks can be bought, sold, and traded, with some services specifically dependent on IPv4 tech.

However, none of that means that IPv6 failed. It’s just been maturing slowly, behind the scenes, ready to keep the internet ticking over with the next billion devices that come online.