I was setting up my laptop for traveling and adding Wireguard VPN configuration.
The Wireguard config generated by router only contains IPv4 address (10.0.5.x), and while testing the VPN to my surprise “what is my ip” websites can find my IPv6 address (I USB tethered mobile connection to my laptop).
It looks like NetworkManager does nothing about IPv6 connection if VPN doesn’t have IPv6 settings, which is bad for road warrior type of VPN configuration.
Is there an easy toggle to turn of IPv6 if VPN is connected and otherwise? Or is only option to disable all IPv6 no matter what?
Best to set a firewall rule with nftables to block non-vpn traffic from leaving (you should also do the save for IPv4 traffic to prevent leaks in case the tunnel disconnects)