OpenL2TP is an L2TP client/server written
specifically for Linux. It has been designed for
use as an enterprise L2TP VPN server or for use in
commercial, Linux-based, embedded networking
products. It consists of a daemon, openl2tpd,
which handles the L2TP control protocol exchanges
for all tunnels and sessions, a plugin for pppd to
allow its PPP connections to run over L2TP
sessions, a Linux kernel driver for efficient
datapath, and a command line application for
management.