OpenAddict.com says, It is possible to spawn a completely jailed second (or many!) operating system within a modern FreeBSD install. Doing so can be tricky, but here I will document the method that I have found works for me. The first most important resource about jails, is the man page, and many of the examples that you will see are basically straight following of the man page. Once you are done, each jail will operate as if its a complete independant operating system. Read more.