The message is below when I run "xl2tpd -D"
xl2tpd[7902]: setsockopt recvref[22]: Protocol not available
xl2tpd[7902]: This binary does not support kernel L2TP.
xl2tpd[7902]: open_controlfd: Unable to open /var/run/xl2tpd/l2tp-control for reading.
It means the kernel doesn't support kernel L2TP, and it will need to recompile the kernel.
