- IPv4 is the long-established addressing system, but its supply of addresses is effectively exhausted.
- IPv6 provides a vastly larger pool of addresses, designed to meet long-term demand.
- Many connections run dual-stack, supporting both IPv4 and IPv6 at the same time during the transition.
- Techniques such as CGNAT and IPv6 help providers cope with the shortage of IPv4 addresses.
- For most users the change is invisible, as devices and services handle both protocols automatically.
IPv4 addresses have effectively run out, so IPv6 provides a far larger pool. Many connections run both at once (dual-stack). The transition is mostly invisible to users, with devices handling both protocols automatically.
Last reviewed: June 2026
What IP versions are
An IP address identifies a connection on the internet, and there are two versions of the addressing system in use: IPv4 and IPv6. IPv4 is the older, long-established system that the internet grew up on. IPv6 is the newer system, created to solve a fundamental limitation of IPv4. For most users the difference is invisible, because devices and services handle whichever version is needed automatically. Understanding the distinction helps make sense of terms that appear in router settings and provider information, and explains some of the engineering behind modern broadband.
The two versions do the same basic job of addressing connections, but they differ enormously in how many addresses they can provide, which is the heart of why the transition is happening.
Why IPv4 ran short
IPv4 uses a format that allows for roughly four billion addresses. That sounded ample when the internet was young, but the explosion of connected devices, from computers and phones to smart home gadgets, has far outstripped it. The available pool of IPv4 addresses is effectively exhausted, meaning there are not enough unique addresses to give every device its own. This shortage is the driving force behind both the workarounds providers use and the move to IPv6, which was designed specifically to remove the limit.
| Aspect | IPv4 | IPv6 |
|---|---|---|
| Address supply | Effectively exhausted | Vast, not a practical concern |
| Address format | Shorter, older format | Much longer format |
| Sharing workarounds | Often uses CGNAT | Each device can have its own address |
| User experience | Works as normal | Works as normal, mostly invisible |
How IPv6 works
IPv6 uses a much longer address format, which expands the number of possible addresses to a scale so vast that exhaustion is not a practical concern. This abundance means every device can have its own unique address without the sharing techniques that IPv4 scarcity forces. IPv6 also brings some technical improvements in how addresses are assigned and how traffic is handled. For the user, the key point is simply that IPv6 removes the address shortage that constrains IPv4, providing room for continued growth in connected devices.
Dual-stack deployment
Because so much of the internet still relies on IPv4, the transition to IPv6 is gradual rather than a sudden switch. Many connections run what is called dual-stack, supporting both IPv4 and IPv6 at the same time. This lets a device reach IPv6 services over IPv6 and IPv4 services over IPv4, ensuring everything continues to work during the transition. Dual-stack is the practical bridge between the two systems, and it is why users rarely notice which protocol is being used at any given moment. The device and the network select the appropriate one automatically.
How providers cope with the shortage
Providers use two main approaches to manage the IPv4 shortage. The first is CGNAT, or Carrier-Grade NAT, which shares a single public IPv4 address among many customers, conserving the scarce addresses. The second is deploying IPv6, which sidesteps the shortage entirely by providing abundant addresses. Many providers use a combination, offering IPv6 alongside IPv4 and using CGNAT where needed. These approaches keep the internet working despite the exhaustion of IPv4, though CGNAT can have side effects for specific uses such as home hosting.
Practical implications for users
For everyday use, the transition is largely invisible. Browsing, streaming, video calls and apps all work regardless of which protocol carries the traffic, because devices and services handle both. The main practical implications arise in specific cases. Where CGNAT is used to stretch IPv4, hosting a service or certain remote access can be affected, as covered in guidance on static IP addresses. IPv6 can ease some of these cases by giving a connection its own address. Otherwise, most households neither need to know nor notice which version is in use.
Does IPv6 make the internet faster
A common question is whether IPv6 improves speed. In general, IPv6 does not make a connection faster in the way a higher-speed package would; the line speed is set by the broadband service, not the addressing system. IPv6 can, in some situations, allow more direct routing by avoiding the address-sharing workarounds that IPv4 scarcity requires, which may help certain connections marginally. The main benefit of IPv6 is removing the address shortage and supporting growth, rather than delivering a noticeable everyday speed increase.
Checking which your connection uses
Households curious about which protocol their connection uses can check through online tools that report whether a connection has IPv4, IPv6 or both, or through the router and device network settings. Many UK connections now support IPv6 in addition to IPv4, though deployment varies between providers. For most people the result is of interest rather than importance, since both protocols are handled automatically. Where IPv6 matters, for example to avoid certain CGNAT limitations, knowing whether it is available helps in choosing or configuring a connection.
The direction of travel
The long-term direction is clear: IPv6 is the future of internet addressing, because it solves the fundamental shortage that IPv4 cannot. The transition is gradual and will continue for some time, with dual-stack bridging the two systems and CGNAT filling gaps where IPv4 is stretched. For users, the reassuring conclusion is that the internet continues to work seamlessly throughout, with the underlying change handled by providers and devices. Awareness of the basics is useful mainly for understanding settings and for the small number of cases where the difference has a practical effect.
IPv6 and connected home devices
The growth of connected home devices is part of why IPv6 matters. Smart speakers, cameras, thermostats, televisions and many other gadgets each need to communicate over the internet, and the number of such devices in a typical home has risen steadily. Under IPv4 scarcity, all of these share addresses through techniques such as the network address translation built into home routers, which works but adds complexity. IPv6, with its abundant addresses, can give devices their own addresses directly, which simplifies how they connect. For households this happens automatically, but it illustrates why the larger address space is increasingly useful as homes fill with connected equipment.
Frequently Asked Questions
What is IPv6?
IPv6 is the newer internet addressing system, created to solve the address shortage of IPv4. It uses a much longer address format, providing a vastly larger pool of addresses so that every device can have its own. It does the same basic job as IPv4 but removes the limit on the number of addresses.
Does my broadband use IPv4 or IPv6?
Many UK connections support both at once, known as dual-stack, though deployment varies between providers. Devices and services select the appropriate version automatically, so the choice is usually invisible. Online tools and router settings can report whether a connection has IPv4, IPv6 or both.
Will IPv6 make my internet faster?
Generally no. The line speed is set by the broadband package, not the addressing system, so IPv6 does not make a connection faster in the way a higher-speed package would. It can allow more direct routing in some cases, but its main benefit is removing the address shortage rather than boosting everyday speed.
What is dual-stack broadband?
Dual-stack means a connection supports both IPv4 and IPv6 at the same time. A device can then reach IPv6 services over IPv6 and IPv4 services over IPv4, so everything keeps working during the transition. It is the practical bridge between the two systems and is why users rarely notice which is in use.
Do all devices support IPv6?
Most modern devices and operating systems support IPv6, and they handle both protocols automatically where the network provides them. Some older equipment may support only IPv4. Because dual-stack connections offer both, devices use whichever is appropriate, so a mix of capabilities continues to work.
How does IPv6 relate to CGNAT?
Both address the IPv4 shortage. CGNAT shares one public IPv4 address among many customers to conserve scarce addresses, while IPv6 sidesteps the shortage by providing abundant addresses. IPv6 can ease some limitations that CGNAT causes for uses such as home hosting, by giving a connection its own address.
