The quick answer: open What is my IP. If you see a value under both IPv4 and IPv6, your connection is dual-stack — IPv6 is working. If only IPv4 shows a value and IPv6 says "Not detected", you're on an IPv4-only connection. Everything else in this article is about why and what to do about it.
What IPv6 actually is
IPv6 is the successor to IPv4. The world ran out of new IPv4 addresses years ago; IPv6 gives us effectively an unlimited pool. An IPv6 address looks like 2001:db8::1 — eight groups of hex characters, 128 bits total. An IPv4 address looks like 203.0.113.42 — four numbers, 32 bits total. Most big services (Google, Facebook, Cloudflare, Netflix) fully support IPv6. The gap is at the ISP level: many home broadband networks still don't hand out IPv6 to customers.
Why it matters (a bit, not enormously)
In 2026 most of the internet still works fine over IPv4. A dual-stack connection gives you:
- Direct connections to IPv6-native services without going through Carrier-Grade NAT, which can matter for gaming latency, some peer-to-peer apps, and running your own servers.
- A unique address per device, rather than sharing your public IP with every other device behind your router. Less relevant for most home users, more relevant if you're self-hosting.
- Future-proofing. Some mobile networks and large ISPs are already IPv6-first, with IPv4 provided as a translation layer. Dual-stack is the path of least resistance.
If you're a typical home user browsing websites, the lack of IPv6 is almost never the reason something is broken. Don't pay extra to "get IPv6" on that basis alone.
Why you might not have it
Common causes of an IPv4-only connection:
- Your ISP doesn't provide IPv6. Some UK providers still don't. Virgin Media notably doesn't as of writing; BT, Sky, and most mobile networks do.
- Your router hasn't been configured for IPv6. ISP-supplied routers usually handle this automatically. Third-party routers may need IPv6 enabled manually in the WAN settings.
- Your VPN only tunnels IPv4. Several popular VPNs do this. Your underlying connection might have IPv6 — but the VPN doesn't forward it, so the checker doesn't see it.
- A captive portal or hotel Wi-Fi is running NAT over IPv4 only.
How to tell what's causing it
Turn off the VPN, if you're using one, and reload What is my IP. If IPv6 appears, your VPN was the blocker. If it's still missing, check your router's admin page — most routers show an IPv6 status on the main dashboard or WAN status page. No IPv6 there means it's not reaching you from the ISP.
What to do if you want IPv6 and don't have it
- Check your ISP's help pages — many let you enable IPv6 via an account setting or a router-firmware update.
- If your router is more than a few years old, replace it. Any modern Wi-Fi 6 / 6E / 7 router supports IPv6 by default.
- Try a different VPN provider or check whether yours has an IPv6-enabled beta client.
- Enable an IPv6 tunnel broker like Hurricane Electric's free service. This is an advanced step and only worth doing if you have a specific reason to need IPv6.
The practical answer for most people: don't worry about it unless something you want to do depends on it. If the checker says IPv4 only, that's fine; most of the internet still works that way.