How the Internet Is Transitioning from IPv4 to IPv6

Explore the main technical approaches used to bridge IPv4 and IPv6 as the internet gradually transitions.

Why Transition from IPv4 to IPv6 at All?

IPv4's addressing system can represent only about 4.3 billion unique addresses, and the explosive growth in the number of connected devices worldwide has led to a shortage of available addresses. IPv6, built on 128 bits, provides an address space so vast that exhaustion is essentially a non-issue.

Dual Stack

The most widely used approach, where a single device or network supports both IPv4 and IPv6 at the same time and automatically communicates using whichever protocol the destination server supports. Most ISPs, routers, and operating systems now default to this approach, so the transition happens largely without users noticing.

Tunneling

A stopgap method that wraps IPv6 packets inside IPv4 packets so they can pass through network segments that don't yet support IPv6 natively. Technologies like 6to4, 6rd, and Teredo encapsulate IPv6 data inside IPv4 packets, letting it travel across IPv4-only segments before being unwrapped on the other side -- a workaround used during the transition period before a network is fully upgraded.

NAT64 / DNS64

A method that lets a device on an IPv6-only network reach servers that only support IPv4, by translating addresses between the two protocols. Some mobile carrier networks are internally IPv6-only, so connecting to older IPv4-only websites or servers requires an intermediary that translates the request. NAT64 converts the IPv6 request into IPv4 and forwards it, while DNS64 supplies the address information needed to make that translation work.

How Far Has the Transition Actually Gotten?

Most modern operating systems, routers, and carriers now support IPv6, but a complete worldwide transition still has a long way to go. Many carriers and large websites already support IPv6, and most current phones and routers can handle it by default, but a fair number of home networks and older websites or equipment still prioritize IPv4. Exact adoption percentages vary by source and point in time, so it's safer to think of this as an ongoing dual-stack transition period than to fixate on a specific number.

What Does This Actually Mean at Home?

In most households, the router and internet provider handle all of this automatically, so users rarely need to think about which protocol is in use. That said, if a particular website or online game keeps having connection issues, toggling IPv6 on or off in your router's settings is one troubleshooting step worth trying.

Curious about the difference between IPv4 and IPv6 themselves?

If you're more interested in the addresses themselves rather than how the transition works, a dedicated guide comparing IPv4 and IPv6 is a good place to start.

Want to understand IPv6 address formats?

For a deeper look at how IPv6 addresses are structured and the different address types, a dedicated guide on IPv6 address types covers that in detail.

Frequently Asked Questions

How can I tell if my internet connection is using IPv6?

A variety of online IPv6 test sites can tell you whether your current connection is using IPv4, IPv6, or both. In most dual-stack setups, though, the switch happens automatically without requiring any action on your part.

Once the transition to IPv6 is complete, will IPv4 stop working entirely?

Not immediately. Because a large amount of older equipment and services still rely on IPv4, a dual-stack transition period where both protocols coexist is expected to continue for a considerable time.