- [FreeS/WAN](http://www.freeswan.org/)
- [GVPE](http://savannah.gnu.org/projects/gvpe/)
- [l2tpd](http://sourceforge.net/projects/l2tpd)
- [Nest](http://www.targeted.org/nest/)
- [OpenS/WAN](http://www.openswan.org/)
- [OpenVPN](http://openvpn.sourceforge.net/)
- [FreeS/WAN](http://www.freeswan.org/)
- [GVPE](http://savannah.gnu.org/projects/gvpe/)
- [l2tpd](http://sourceforge.net/projects/l2tpd)
- [Nest](http://www.targeted.org/nest/)
- [OpenS/WAN](http://www.openswan.org/)
- [OpenVPN](http://openvpn.sourceforge.net/)