IPv6 Leak Test

Check if your VPN is leaking IPv6 traffic and exposing your real identity.

Takes about 5-10 seconds

How This Test Works

  1. We query our IPv4-only endpoint (v4.zend2.com) to get your IPv4 address and network info
  2. We query our IPv6-only endpoint (v6.zend2.com) to check if you have IPv6 connectivity
  3. We use WebRTC ICE candidate gathering to detect any IPv6 addresses your browser might expose
  4. We compare the ASN (network owner) of your IPv4 and IPv6 addresses
  5. If IPv6 comes from a different network (your ISP) while IPv4 is from your VPN, that's a leak

Privacy note: This test does not log any IP addresses or personal data.

What Is an IPv6 Leak?

An IPv6 leak occurs when your IPv6 internet traffic bypasses your VPN tunnel and travels directly through your Internet Service Provider (ISP). This can happen even when your VPN is connected and working correctly for IPv4 traffic.

When you connect to a VPN, you expect all your internet traffic to be encrypted and routed through the VPN server. However, many VPNs were designed primarily for IPv4 and don't properly handle IPv6 traffic. This creates a "split tunnel" situation where:

  • IPv4 traffic goes through your VPN (protected)
  • IPv6 traffic goes directly to your ISP (exposed)

Why IPv6 Leaks Matter

Identity Exposure

Your real IPv6 address can be linked to your ISP account and physical location.

Silent Failure

IPv6 leaks happen silently while your VPN shows "connected".

Growing IPv6 Adoption

More websites support IPv6, making leaks more likely to expose you.

Unique Identifier

IPv6 addresses are often static and unique, making them excellent tracking identifiers.

How to Fix IPv6 Leaks

1. Use a VPN with IPv6 Support: Premium VPNs like Mullvad, NordVPN, and ExpressVPN offer full IPv6 support.

2. Enable IPv6 Leak Protection: Many VPNs offer an "IPv6 leak protection" setting that blocks all IPv6 traffic while connected.

3. Disable IPv6 on Your Device:

  • Windows: Network adapter settings → IPv6 → Uncheck
  • macOS: System Preferences → Network → Advanced → TCP/IP → Configure IPv6: Off
  • Linux: Add net.ipv6.conf.all.disable_ipv6 = 1 to sysctl.conf

4. Disable IPv6 on Your Router: For network-wide protection, disable IPv6 in your router settings.

Frequently Asked Questions

An IPv6 leak occurs when your IPv6 traffic bypasses your VPN tunnel and goes directly through your ISP, exposing your real IPv6 address even while connected to a VPN. This can reveal your identity and location to websites and services you visit.

IPv6 leaks happen because many VPNs only tunnel IPv4 traffic, leaving IPv6 traffic to route through your regular ISP connection. Some VPNs lack proper IPv6 support or fail to block IPv6 when they cannot tunnel it.

You can fix IPv6 leaks by:

  1. Using a VPN that fully supports IPv6 tunneling
  2. Enabling IPv6 leak protection in your VPN settings
  3. Disabling IPv6 on your device or router
  4. Using a VPN that blocks IPv6 traffic entirely

Having no IPv6 connectivity is not a security problem-it means you cannot have an IPv6 leak. However, it may reduce your internet reachability as more services adopt IPv6-only infrastructure.

Yes, WebRTC can expose both IPv4 and IPv6 addresses through ICE candidate gathering, even when using a VPN. This test checks for WebRTC IPv6 leaks in addition to standard HTTP-based detection.

Run this test while connected to your VPN. If you see an IPv6 address that belongs to your VPN provider's network (same ASN as your IPv4), your VPN supports IPv6. If you see your ISP's IPv6 address, your VPN is leaking. If you see no IPv6, your VPN may be blocking it (which is also safe).

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