IPv6 leak test

If your VPN only supports IPv4 but your connection also uses IPv6, your real IPv6 leaks in the clear, bypassing the protection.

What does this result mean?

• No IPv6 detected → you have no IPv6 connectivity, or your VPN blocks it correctly. No leak possible. ✓
• A public IPv6 detected → you have active IPv6. Check whether it matches your VPN server or your ISP:
  • If it matches the VPN → all good
  • If it matches your ISP → confirmed IPv6 leak

How do I fix an IPv6 leak?

Option 1 — Use a VPN that handles IPv6 natively:

• NordVPN — blocks IPv6 by default on all apps
• ExpressVPN — IPv6 protection enabled
• Proton VPN — supports IPv6 on its servers
• Mullvad — blocks IPv6 by default

Option 2 — Disable IPv6 manually on your system:

• Windows: Control Panel → Network and Sharing Center → Change adapter settings → Properties → uncheck "Internet Protocol Version 6 (TCP/IPv6)"
• macOS: System Settings → Network → Advanced → TCP/IP → Configure IPv6 → Off
• Linux: sudo sysctl -w net.ipv6.conf.all.disable_ipv6=1
• Router: admin interface → disable IPv6 (recommended if your VPN doesn't handle it)

Why is IPv6 a problem?

IPv6 is the new version of the internet protocol, gradually being rolled out by ISPs. Many older VPNs only support IPv4. The result: your IPv4 traffic goes through the VPN, but your IPv6 traffic exits directly through your ISP — revealing your real IPv6 and identity.

It's a particularly insidious leak because it's invisible to the user: everything seems to work normally, but part of your traffic is unprotected. Most modern decent VPNs block IPv6 by default or route it through the tunnel.

Related tools

• What is my IP? — detect your public IP
• DNS leak test — check your DNS goes through the VPN
• WebRTC leak test — check your real IP isn't exposed