VPN tunnel to FritzBox via IPSec IKEv1 with mutual PSK and Xauth

[FaDo]

maybe this can help you. I haven’t tested it yet:

Gl-ar300 l2pt vpn shellfire over wwan

You have successfully configured L2TP, haven’t you? Can you share your configuration? If you want all data to pass through the wwan, try adding the following routing rules ip route add 0.0.0.0/1 dev tun ip route add 128.0.0.0/1 dev tun