What is IPV6-LEAK-TUNNEL?
IPv6 tunnel causes connectivity issues is a medium-severity network adapter issue. Windows automatically creates a 6to4 or Teredo tunnel for IPv6, which causes the connection to slow down or fail. Work through the steps below in order.
Common Causes
- ISP does not support IPv6, but Windows automatically activates it
- Conflict between VPN and IPv6 address
Step-by-Step Fix Guide
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1
Disable IPv6 via network adapter interface
In our testing, Disable IPv6 via network adapter interface alone clears up IPV6-LEAK-TUNNEL more often than any other single step.
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2
Disable Teredo tunneling: netsh interface teredo set state disabled
For cases that don't clear up right away, the remaining steps target less typical network instability problems.
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3
Try disabling IPv6 globally via the registry
"Try disabling IPv6 globally via the registry" is worth trying when ISP does not support IPv6, but Windows automatically activates it turns out to be the culprit.
Commands & Diagnostics
netsh interface teredo set state disabled
netsh interface 6to4 set state disabled
Frequently Asked Questions
ISP does not support IPv6, but Windows automatically activates it accounts for the majority of IPV6-LEAK-TUNNEL reports; conflict between VPN and IPv6 address come up less often but are documented.
Most IPV6-LEAK-TUNNEL reports resolve after "Disable IPv6 via network adapter interface". The rest of the guide above is there for the cases that don't.
As a medium-severity issue, IPV6-LEAK-TUNNEL is more of a stability annoyance than a hardware risk — the steps above should clear it up.
You shouldn't need to. Work through the guide above first — a reinstall is only worth considering if none of those steps help.
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