Before I built a wall I’d ask to know What I was walling in or walling out, And to whom I was like to give offence. Something there is that doesn’t love a wall, That wants it down.

—Robert Frost “Mending Wall”

FreeBSD and OpenBSD are often considered the “other” free operating systems besides Linux. However, in recent Netcraft surveys, the five most reliable web sites on the planet run FreeBSD. OpenBSD, too, is deployed on thousands of security servers around the world. These two BSD-based operating systems are rapidly gaining traction in educational institutions, non-profits, and corporations worldwide.

Plenty of books exist to help you get a FreeBSD or OpenBSD system off the ground. All of them touch on security, but most only dedicate a chapter to it. In sharp contrast, we think it’s worth spending an entire book on the subject. FreeBSD and OpenBSD are rife with security “building blocks” that you can use to really take security and “kick it up a notch.”

These operating systems have kernel options and filesystem features that go well beyond traditional Unix permissions and controls. This power and flexibility is valuable, but the colossal range of possibilities will leave you dizzy if you don’t take things one step at a time. Mastering FreeBSD and OpenBSD Security complements existing books on FreeBSD and OpenBSD administration. Where others help you achieve functionality, we help you build security-minded deployments. This book walks you through the installation of a ...