A long time ago, a very smart guy asked a very simple question. "Why do firewalls have to be big, slow, and hard to configure?" And he created m0n0wall.

"m0n0wall was a project aimed at creating a complete, embedded firewall software package that, when used together with an embedded PC, provided all the important features of commercial firewall boxes (including ease of use) at a fraction of the price (free software)."

At this, it was amazingly successful. So successful that the FreeBSD based core was used as a basis for several other projects such as pfSense, Askozia, FreeNAS, and nas4free. Recently, a grandchild of m0n0wall was spawned from pfSense, OPNSense.

But, m0n0wall has retired now, and some of us still feel the need for a small and lean firewall. SmallWall is that firewall.