What is the IPv6 leak?
Most of the current websites support only IPv4, while there are quite a few internet service providers (ISPs) that support both IPv4 and IPv6.
Here is a real-life example: your ISP is using both protocols and you are connecting to some website or service which supports only IPv4. This is where IPv6 leak may happen - the requests you are sending to that website or service will contain both your IPv4 and IPv6 IP addresses.
It can happen even if you are using a VPN but this is not the case with NordVPN.
How does NordVPN protect you from IPv6 leaks?
NordVPN has integrated IPv6 leak protection. You can read more about it here: https://nordvpn.com/blog/nordvpn-implements-ipv6-leak-protection/
Depending on your device and/or network, you can disable the usage of IPv6 altogether - in 99.9% cases it will have no extra effect on your internet usage - IPv6 adoption process is slow, and almost all services allow access through IPv4.
How else can you protect yourself from IPv6 leak?
You can disable IPv6 in your network completely by changing your router configuration. Each router is different but most have the ability to turn IPv6 completely off - in that case, you won't have to change anything in your devices.
For information on how to disable it on your router, check your router's user manual. If you are not able to disable it on the network (for example, when using public networks), you can disable it on your device instead: