What Is an IPv6 Leak?
An IPv6 leak can occur when a VPN routes IPv4 traffic but leaves IPv6 traffic using the normal network path.
How it works
On a dual-stack connection, websites may choose IPv6 if it is available. If a VPN is expected to cover all traffic but does not handle IPv6, a site could see an IPv6 address from the normal ISP connection. IPv6 itself is not a leak or a problem; it matters only when it conflicts with your intended routing or privacy setup.
A practical example is visiting a dual-stack website after connecting a VPN. If the site records an IPv6 address assigned by the ordinary network while IPv4 comes from the VPN, the routes are not behaving consistently with an all-traffic expectation.
Some VPN products intentionally disable IPv6, while others tunnel it. Either approach can be valid when documented. The important part is knowing which behavior your device uses and whether it suits the task.
Practical guidance
- Check whether your connection uses IPv6.
- Read your VPN provider's IPv6 support documentation rather than assuming behavior.
- Test after connecting to the VPN and compare the visible address family with your normal connection.
Common question
Should I turn IPv6 off? Only if your provider recommends it for a specific compatibility reason. Disabling it is not a universal privacy solution.