Does disabling IPv6 cause problems?

For most users, no. Windows, macOS, and Linux all handle IPv4 fallback gracefully. Some corporate networks and ISPs prefer IPv6, and disabling it may affect connection priority on those networks. On home networks, the practical impact is usually zero.

My VPN says it supports IPv6. Why is it still leaking?

VPN 'IPv6 support' can mean different things: some providers tunnel IPv6 through the VPN; others block all IPv6 traffic while the VPN is active. If the leak persists after enabling IPv6 settings, try disabling IPv6 at the OS level as a guaranteed fallback, and report the issue to your VPN provider.

How to Fix an IPv6 Leak — Windows, macOS & Linux

Q: Why does my VPN not protect my IPv6 address?

Many VPN protocols and clients were designed when IPv4 was dominant. If the VPN only tunnels IPv4 traffic, IPv6 connections route natively through your ISP, exposing your real IPv6 address to sites you visit. VPNs that support IPv6 either tunnel it through the VPN or block it entirely.

Q: Is it safe to disable IPv6?

For most home users, disabling IPv6 causes no noticeable problems. Most internet services support both IPv4 and IPv6, and your device will fall back to IPv4 when IPv6 is disabled. Disabling it may slightly affect performance on networks where IPv6 would have been faster, but this is rarely significant.

Q: How do I know if my ISP uses IPv6?

Run the IPv6 Leak Test at myipscan.net/tools/ipv6-leak-test without a VPN. If an IPv6 address is shown, your ISP has assigned you an IPv6 address and your connection uses dual-stack (IPv4 and IPv6). If no IPv6 address appears, your ISP does not provide IPv6 and you are not at risk of an IPv6 VPN leak.

Before you start: Connect your VPN, then open the IPv6 Leak Test. If you see an IPv6 address that belongs to your ISP, this guide is for you. If no IPv6 address appears, your ISP does not provide IPv6 and you are not at risk.

Step 1 — Confirm the leak

Open the MyIPScan IPv6 Leak Test with your VPN active. If an IPv6 address appears and the ASN or ISP name belongs to your home internet provider, your IPv6 traffic is routing natively outside the VPN tunnel.

For context: as of 2024, over 45% of internet users have IPv6 connectivity. If your ISP is among them and your VPN does not handle IPv6, every site you visit can see your real IPv6 address even if your IPv4 is hidden.

Step 2 — Enable IPv6 protection in your VPN

Try the VPN-side fix first:

Open your VPN client's Settings.
Look for: IPv6 leak protection, Block IPv6, IPv6 tunnel, or Disable IPv6.
Enable the setting.
Disconnect and reconnect the VPN.
Re-run the IPv6 Leak Test.

If no IPv6 address appears, the fix worked. If the leak persists, proceed to the OS-level fix for your operating system below.

Step 3 — Disable IPv6 on Windows

Open Control Panel > Network and Sharing Center > Change adapter settings.
Right-click your active connection (Wi-Fi or Ethernet) and select Properties.
In the list, find Internet Protocol Version 6 (TCP/IPv6) and uncheck it.
Click OK.
Reconnect your VPN and re-test.

You may need to repeat this for all active adapters (both Wi-Fi and Ethernet) if you switch between them.

Step 4 — Disable IPv6 on macOS

Open System Settings (macOS Ventura and later) or System Preferences (earlier).
Go to Network.
Select your active connection (Wi-Fi or Ethernet) and click Details (or Advanced).
Go to the TCP/IP tab.
Set Configure IPv6 to Off or Link-local only.
Click OK, then Apply.
Reconnect your VPN and re-test.

Step 5 — Disable IPv6 on Linux

Temporary (until next reboot):

sudo sysctl -w net.ipv6.conf.all.disable_ipv6=1
sudo sysctl -w net.ipv6.conf.default.disable_ipv6=1

Persistent (survives reboots):

Add these lines to /etc/sysctl.conf:

net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1

Then apply: sudo sysctl -p

Reconnect the VPN after applying and re-run the leak test.

Step 6 — Verify

Run the IPv6 Leak Test again. The result should show no IPv6 address. If your ISP IPv6 address still appears, check that:

You modified the correct network adapter (the one currently in use)
The VPN was reconnected after the change
No other network interfaces are active (e.g. a separate USB Ethernet adapter)

Related guides and tools

IPv6 Leak TestVerify your IPv6 address is not exposed. VPN Leak TestCombined IP + DNS + WebRTC + IPv6 test. Fix a VPN LeakGeneral guide covering all four leak types. Fix a DNS LeakStop DNS queries going to your ISP. Disable WebRTCBlock browser WebRTC IP exposure. What Is a VPN Leak?Full explanation of all VPN leak types.

Frequently asked questions

Why does my VPN not protect my IPv6 address?

Many VPN clients were built when IPv4 was dominant and do not route IPv6 traffic through the tunnel. When IPv6 is available, it connects natively through your ISP, bypassing the VPN. VPNs handle this by either tunnelling IPv6 or blocking it entirely — check your VPN's settings to see which approach it uses.

Is it safe to disable IPv6?

For most home users, yes. Almost all internet services support IPv4 fallback. You may see slightly lower performance on ISPs that route IPv6 more efficiently than IPv4, but this is rarely noticeable. Enterprise environments may rely on IPv6 for internal services — check with your network admin before disabling it in a corporate context.

How do I know if my ISP uses IPv6?

Run the IPv6 Leak Test without your VPN connected. If an IPv6 address appears, your ISP provides IPv6. If no address appears, your ISP does not assign IPv6 and you are not at risk of an IPv6 VPN leak.

My VPN says it supports IPv6 but I still have a leak. Why?

"IPv6 support" in VPN marketing can mean different things: some providers tunnel IPv6 through the VPN; others block all outbound IPv6; some only block it on certain platforms. If the leak persists after enabling the IPv6 setting, fall back to disabling IPv6 at the OS level and report the issue to your VPN provider.

Will re-enabling IPv6 undo the fix?

Yes. If you re-enable IPv6 on your network adapter while using a VPN that does not support it, the leak will return. If you need IPv6 for other reasons, switch to a VPN that explicitly supports IPv6 tunnelling or blocking, and test with the IPv6 Leak Test after reconnecting.