- [CIPE](http://cipe-linux.sourceforge.net/)
- [cjdns](https://github.com/cjdelisle/cjdns)
- [FairVPN](http://minerva.netgroup.uniroma2.it/fairvpn)
+- [fastd](https://projects.universe-factory.net/projects/fastd/wiki)
- [FreeLAN](http://www.freelan.org/)
- [GVPE](http://software.schmorp.de/pkg/gvpe.html)
- [l2tpd](https://sourceforge.net/projects/l2tpd)