IPv6 is the newer addressing system that lets devices find each other on the internet when IPv4 runs out of addresses

The internet assigns every connected device an address so data packets know where to go, the same way mail needs a street address. Internet Protocol version 4 (IPv4) has been doing this since the 1980s using addresses like 192.168.1.1 — four numbers separated by dots, each ranging from 0 to 255. That system can create about 4.3 billion unique addresses. In the 1990s, engineers realized the world would eventually connect more devices than that.

Internet Protocol version 6 (IPv6) solves this by using a longer address format: eight groups of hexadecimal numbers separated by colons, like 2001:0db8:85a3:0000:0000:8a2e:0370:7334. Hexadecimal means it uses digits 0–9 plus letters A–F, so each position holds more information. IPv6 can create roughly 340 undecillion addresses — a number so large that every grain of sand on Earth could have billions of addresses. Your smartphone, your refrigerator, your car, your security camera, and devices not yet invented can each have their own permanent address.

Most of the internet still runs on both IPv4 and IPv6 at the same time. Your device probably has both an IPv4 address and an IPv6 address right now. The transition has been slow because switching over completely would break older equipment and software that only understands IPv4. So the internet runs in a hybrid state, with newer systems speaking both languages.

Key Takeaways

  • IPv6 uses longer addresses than IPv4, allowing trillions of times more devices to connect to the internet without running out of addresses.
  • Your device likely has both an IPv4 address and an IPv6 address, and they work alongside each other on most modern networks.
  • IPv6 includes built-in security features and better support for real-time applications like video calls, which IPv4 was not designed for.
  • The switch from IPv4 to IPv6 has taken decades because older equipment and software still rely on the older system.

How IPv4 addresses ran out and why IPv6 became necessary

When the internet was small, 4.3 billion addresses seemed like plenty. But the internet grew faster than anyone predicted. By the early 2000s, internet service providers and large companies were buying up address blocks and hoarding them. Some organizations held millions of addresses they did not actively use. Meanwhile, smartphones, tablets, smart home devices, and cloud services all needed their own addresses.

The shortage created a workaround called Network Address Translation (NAT). Instead of giving every device its own public address, a router assigns private addresses to devices on your home network (like 192.168.1.5 for your laptop) and translates them when data goes out to the internet. This kept the shortage from becoming a complete crisis, but it added complexity and made certain types of communication harder. Some applications and services could not work properly behind NAT.

IPv6 eliminates the need for this translation layer. Every device can have its own public address, which simplifies how the internet works and makes certain services faster and more reliable. The Internet Assigned Numbers Authority (IANA) officially ran out of new IPv4 addresses to distribute in 2011, which accelerated the push toward IPv6.

The technical differences between IPv4 and IPv6 addresses

An IPv4 address uses 32 bits of information, written as four decimal numbers: 203.0.113.42. Each number can range from 0 to 255. This format is straightforward for humans to read and remember, but it limits the total number of possible addresses.

An IPv6 address uses 128 bits of information, written as eight hexadecimal groups: 2001:db8:85a3::8a2e:370:7334. The double colon (::) is shorthand for one or more groups of zeros, which makes long addresses shorter to write. Because hexadecimal uses 16 possible values per position instead of 10, each position holds more information. The result is an address space so large that running out is not a realistic concern for the foreseeable future.

IPv6 also built in features that IPv4 added later as patches. IPsec — encryption and authentication for data packets — is part of IPv6 from the start, not bolted on afterward. IPv6 also handles real-time data streams (like video calls) more efficiently because it includes a field for marking which packets belong together and should be treated as a group. IPv4 was designed for email and file transfer, not for the kinds of applications people use today.

Why the switch to IPv6 has taken so long

Switching the entire internet to a new protocol is like replacing the plumbing in a city while people still live there. Every router, every server, every network device needs to understand IPv6. Older equipment that only speaks IPv4 will not work with pure IPv6 networks. Companies have had to buy new hardware or update software, which costs money and requires planning.

Internet service providers have been slow to deploy IPv6 because their existing IPv4 infrastructure still works. Some ISPs still do not offer IPv6 to residential customers, even though the technology has been available for over 20 years. Large websites and services have been faster to adopt it — Google, Facebook, and Netflix all support IPv6 — but smaller services have not.

The hybrid approach (running both IPv4 and IPv6 simultaneously) has reduced the urgency. Devices can still reach IPv4-only services through translation mechanisms, so there is no when ready crisis forcing everyone to switch. This has extended the transition period indefinitely.

How your device uses IPv4 and IPv6 at the same time

When you connect to the internet, your device usually gets both an IPv4 address and an IPv6 address from your router or internet service provider. Your operating system (Windows, macOS, iOS, Android) handles both automatically. When you visit a website, your device tries to connect using IPv6 first. If the website does not support IPv6, your device falls back to IPv4.

This dual-stack approach means you do not have to choose between the two systems. Your device speaks both languages and picks the right one for each connection. You will not see this happening — it occurs in the background. The only time you might notice is if a website or service has a problem with IPv6 support, in which case it might load slowly or fail until your device switches to IPv4.

Some networks use translation mechanisms to bridge the gap between IPv4 and IPv6. These systems convert packets from one format to the other so devices on different protocol versions can communicate. The most common is called NAT64, which translates between IPv6 addresses and IPv4 addresses at the network edge.

What IPv6 means for security and performance

IPv6 was designed with security in mind from the start. Every IPv6 packet can be encrypted and authenticated using IPsec, which is built into the protocol rather than added as an afterthought. This does not mean IPv6 is automatically more find — you still need firewalls, you still need to keep software updated, and you still need to use strong passwords. But the foundation is stronger.

Performance improvements come from better handling of data streams. IPv6 includes a field called the flow label that lets routers identify which packets belong to the same conversation (like all the packets in a video call). Routers can then prioritize or handle those packets as a group, rather than treating each packet individually. This is especially useful for real-time applications where delay matters.

IPv6 also simplifies network configuration. With IPv4, devices often need manual setup or a separate service (DHCP) to assign addresses. IPv6 devices can often configure themselves automatically, which reduces the work network administrators have to do.

Where IPv6 adoption stands today

As of 2024, roughly 35 to 40 percent of internet traffic uses IPv6, depending on which region and which measurement service you look at. This varies significantly by country and by internet service provider. Some regions in Asia and Europe have higher IPv6 adoption than North America. Major technology companies and content providers have deployed IPv6, but many smaller services and older systems still rely on IPv4 only.

Mobile networks have been faster to adopt IPv6 than fixed broadband. Most smartphones can reach IPv6 services, and major carriers support it. Home broadband adoption depends on your ISP — some offer it by default, others require you to request it, and some do not offer it at all.

The transition will likely continue for decades. IPv4 will not disappear; instead, both systems will coexist. New devices and services will use IPv6, while older systems will keep using IPv4. The internet will remain a hybrid network, with translation layers handling communication between the two.

Frequently Asked Questions

Do I need to do anything to use IPv6?

No. Your device and your internet service provider handle IPv6 automatically if it is available on your network. You do not need to change settings or install anything. If your ISP does not offer IPv6, your device will continue using IPv4 without any problems.

Will IPv4 ever completely disappear?

Probably not in your lifetime. IPv4 will remain in use for decades because too much equipment and software depends on it. The internet will likely remain a hybrid network indefinitely, with both protocols running side by side.

Is IPv6 faster than IPv4?

Not inherently. IPv6 packets are slightly larger, which could theoretically make them slower. But IPv6 handles certain types of traffic (like video streaming and real-time applications) more efficiently because of built-in features. For most everyday browsing, you will not notice a speed difference.

Can I check if my device has an IPv6 address?

Yes. On Windows, open Command Prompt and type ipconfig. Look for a line starting with "IPv6 Address". On Mac or Linux, open Terminal and type ifconfig or ip addr. On smartphones, go to Settings and look for network information — most modern phones display both IPv4 and IPv6 addresses.

What happens if a website does not support IPv6?

Your device automatically falls back to IPv4 and connects that way. You will not see any error or notice anything different. The fallback happens in the background, usually in less than a second.