All internet traffic can be routed via an OpenVPN connection using
redirect-gateway def1
in the client .ovpn config file but this is only for IPv4 traffic AFAIK. To also route IPv6 traffic, the ipv6 option would be needed
redirect-gateway def1 ipv6
But this gives the connection warning suggesting it probably isn’t working:
2026-08-05 10:54:38 WARNING: OpenVPN was configured to add an IPv6 route. However, no IPv6 has been configured for OpenVPN Data Channel Offload, therefore the route installation may fail or may not work as expected.
Indeed, testing using https://whatismyipaddress.com/ shows the IPv4 address of the IPFire box (traffic is routed via OpenVPN, as expected) but the IPv6 address of the wifi I’m connected to. Even with the block-ipv6 option, the IPv6 address is still ‘leaked’.
redirect-gateway def1 ipv6
block-ipv6
I’m aware that IPFire does not support IPv6 for security reasons but wondered if it was this decision causing the IPv6 leak I’m seeing above? Or perhaps whether there is an alternative solution to prevent this leak when connected to VPN?
I guess a more general solution could be to always block all in/outbound IPv6 traffic on Windows or antivirus firewall, but I’m unsure whether this may always be an option these days for users home internet or whilst travelling, connecting to wifi or mobile data hotspot. (Any thoughts from anyone with more knowledge on this welcome!)