IPv6 is the newer version of the Internet Protocol, designed to replace IPv4. It has been around since the late 1990s, but adoption only took off in the last decade as the world ran out of IPv4 addresses. Today a large and growing share of traffic to big services like Google already uses IPv6, much of it from mobile phones. Here is what IPv6 is, how it differs from IPv4, and what it means for you.
Why IPv6 exists
An IPv4 address is 32 bits long, allowing about 4.3 billion addresses. That sounded like plenty in 1981. Today there are far more connected devices than that, and the regional internet registries have essentially run out of new IPv4 blocks. Providers cope by sharing addresses with NAT and carrier-grade NAT, and by buying addresses on a secondary market at increasing prices.
IPv6 addresses are 128 bits long. That gives about 3.4 × 1038 addresses – enough for every device ever made to have its own public address, with room to spare.
What an IPv6 address looks like
IPv6 addresses are written as eight groups of four hexadecimal digits separated by colons:
2001:0db8:0000:0000:0000:ff00:0042:8329Two rules make them shorter:
- Leading zeros in a group can be dropped:
0db8becomesdb8,0042becomes42. - One run of consecutive all-zero groups can be replaced with
::.
So the address above becomes 2001:db8::ff00:42:8329. Some addresses worth recognising:
| Address or prefix | Meaning |
|---|---|
::1 | Loopback – your own computer (like 127.0.0.1) |
fe80::/10 | Link-local – works only on the local network segment |
fc00::/7 (usually fd…) | Unique local addresses – private, like 192.168.x.x |
2000::/3 | Global unicast – normal public addresses |
2001:db8::/32 | Reserved for documentation and examples |
The main differences from IPv4
- No NAT needed. Every device gets its own public address. Your router still runs a firewall that blocks unsolicited incoming connections, but devices can be reached directly when you allow it – which makes gaming, video calls and hosting easier.
- Automatic configuration. Devices can build their own address from the network prefix the router announces (called SLAAC), with or without DHCPv6.
- Prefixes instead of single addresses. Your provider gives your router a whole block, typically a /56 or /48, containing 256 or 65,536 separate /64 networks. You can check the sizes with our subnet calculator.
- Privacy addresses. Modern operating systems use temporary, randomly generated addresses for outgoing connections and change them regularly, so your device cannot easily be tracked by its address.
- Several addresses per device. It is normal for a computer to have a link-local address, a stable address and one or more temporary addresses at the same time.
Do you need IPv6?
For everyday browsing, not yet: virtually every website still supports IPv4, and providers translate where necessary. But IPv6 is genuinely useful when:
- your provider uses CGNAT for IPv4 – IPv6 may give you the direct, reachable connection that IPv4 cannot;
- you play online games or use peer-to-peer apps that benefit from direct connections;
- you run servers or remote access at home;
- you work in IT and need to test or support IPv6-only networks, which are increasingly common on mobile.
There is no downside to having IPv6 enabled when it works properly, and it will matter more every year.
How to check and enable IPv6
- Test your connection. Check your device’s network details for an IPv6 address starting with 2 or 3 (not fe80::). If you only see fe80:: addresses, IPv6 is not reaching you from the internet.
- Check your router. In the admin page, look for an IPv6 or “Internet › IPv6” section. Enable it and choose the connection type your provider recommends – commonly “Native”, “DHCPv6” or “Auto” with prefix delegation.
- Check your devices. On Windows, open the network adapter’s properties and make sure “Internet Protocol Version 6 (TCP/IPv6)” is ticked. macOS, iOS and Android enable IPv6 automatically.
- Ask your provider. If the router has no IPv6 address on its WAN side, your provider may not offer IPv6 yet, or may need to enable it for your line.
IPv6 and VPNs
Many VPNs only tunnel IPv4. If your connection has IPv6 and the VPN ignores it, websites that support IPv6 can see your real IPv6 address – a classic leak. Good VPN apps either tunnel IPv6 properly or block it while connected. Check with our VPN check and WebRTC leak test while the VPN is on.
Security considerations
Because IPv6 devices have public addresses, the router’s IPv6 firewall is essential. Most consumer routers block unsolicited incoming IPv6 connections by default – make sure that setting has not been turned off. If you open access to a device, do it with a specific firewall rule rather than disabling the firewall. Remember also that a port forwarding rule for IPv4 does not apply to IPv6; IPv6 needs a separate firewall “allow” rule.
Summary
IPv6 solves the IPv4 address shortage with vastly longer addresses, removes the need for NAT, and configures itself automatically. You do not need to do anything to keep browsing, but enabling IPv6 can improve connectivity – especially behind CGNAT. Test your connection, keep your router’s firewall on, and make sure your VPN handles IPv6.