This project has some great base distributions/versions to create
embedded Linux routers, firewall, bridges, and servers from. I
have personally used LEAF for several years now and make 1U,
2U, half-, and full-slot rack mount appliances with them. There
are many other similar projects out there, but I have found LEAF
to be the most configurable and secure with a minimum of effort
to do exactly what I need. I look forward to using LEAF _much_
more in the fulure.