Your phone is probably using IPv6 right now. Most mobile networks moved to it years ago, and you never noticed, because nothing looked different. The same change is slowly reaching office networks, and that part does need a little attention.
This guide explains what changed, where things stand in 2026, and what a small or mid-sized office should check. No conversion project is required to follow it.
IPv4 and IPv6 in one minute
Every device on the internet needs an address so that data knows where to go. There are two address systems in use.
- IPv4 is the original. Its addresses are 32 bits long and look like
203.0.113.25. That allows about 4.3 billion addresses, which seemed like plenty in the 1980s. - IPv6 is the replacement. Its addresses are 128 bits long and look like
2001:db8:85a3::8a2e:370:7334: eight groups of hexadecimal digits separated by colons, with runs of zeros shortened. That allows about 340 undecillion addresses, a number with 39 digits.
The two systems don't talk to each other directly. A device with only an IPv4 address can't reach a server that has only an IPv6 address without something in the middle translating. That is why the change has taken decades and why most networks run both.
Why the old addresses ran out
The global pool of unassigned IPv4 addresses was handed out in February 2011. The registry for North America ran out of its own supply in September 2015. Since then, IPv4 addresses have been reused, shared, and bought and sold.
You can see the scarcity in pricing. Since February 1, 2024, Amazon Web Services has charged $0.005 per hour for every public IPv4 address, about $3.60 a month each. IPv6 addresses carry no such charge.
What kept IPv4 going is address sharing, known as NAT. Your whole office appears to the internet as one public address, and the firewall keeps track of which computer asked for what. It works, but it adds complications: remote access needs special rules, and two offices that use the same private address range can't be joined by a VPN without workarounds.
Where adoption stands in 2026
About half of Google's users now reach it over IPv6, a milestone reported in April 2026. In the United States the share crossed 50% in February 2025. Mobile carriers and home internet providers lead. Corporate networks trail well behind.
The practical point: many of your customers, and most of your staff when they work from a phone or from home, are already on IPv6, even if your office is not.
What to check in your office
1. You don't have to give up IPv4
The standard approach is called dual stack: the network carries both, and each device uses IPv6 where the other end supports it and IPv4 where it doesn't. Nothing gets switched off.
2. Ask what your internet provider delivers
Many business internet circuits already include IPv6. Ask your provider whether yours does and what address block comes with it. If you're ordering service for a new office, ask before you sign.
3. Make sure the firewall covers IPv6
This is the check that matters most. Windows, Macs and phones have IPv6 switched on by default. If your provider delivers IPv6 and your firewall rules were written only for IPv4, part of your traffic may be passing with less inspection than you think. Either write matching IPv6 rules or block IPv6 at the firewall on purpose. Don't leave it unmanaged.
4. Leave IPv6 on in Windows
Turning IPv6 off on each computer is a common shortcut. Microsoft advises against it, because parts of Windows expect IPv6 to be there. Control it at the firewall instead.
5. Test remote access from a phone
Connect a laptop through a phone hotspot and try your VPN and remote desktop. Mobile networks are often IPv6-first, so this is the quickest way to find out whether remote staff will have trouble.
6. Check your website and email
If your website sits behind a large hosting or content delivery service, it is probably reachable over IPv6 already. Have someone confirm it, along with your email filtering service.
7. Update your records and tools
Address plans, network diagrams, monitoring and logs should all handle IPv6 addresses. An alert that only understands IPv4 will miss half the picture.
When to plan a real migration
For most offices there is no deadline. The sensible moments are the ones when you're changing the network anyway: a new office, a firewall replacement, a new internet provider, or a move to the cloud. Adding IPv6 during that work costs little. Adding it later as a separate project costs more.
If you run several locations or host your own services, it is worth a short review now, so that network design and address planning are done once.
What happened to IPv5?
It existed, briefly. Version number 5 was assigned to an experimental protocol for streaming voice and video, developed decades ago. It was never rolled out to the public, but the number was taken, so the next version became 6.
Sources
- Google IPv6 statistics
- Google hits 50% IPv6 (APNIC, April 2026)
- IPv6 usage in the U.S. surpasses 50% (CircleID)
- AWS public IPv4 address charge (Amazon Web Services)
- RFC 8200: Internet Protocol, Version 6 (IPv6) Specification
- Guidance for configuring IPv6 in Windows (Microsoft)
Figures checked October 2026. Adoption numbers and cloud pricing change; confirm current figures before you rely on them.
