Running Apache in jail can be tricky, this module allows to run Apache in a secure jail prison easy, without creating real jail environment containing copy of /lib, /libexec, /usr/lib, etc, also mod_jail makes it possible to change securelevel into jail prison.
mod_jail is Apache module, that supports 1.3.xx and 2.xx branches, it is similar to mod_chroot, but uses FreeBSD's specific system call - jail that is more secure than chroot, so, it is intended to run on FreeBSD only.
But now there is a jail patch for Apache source code that is based on official chroot patch for Apache 2.2.10, jail and chroot code now is backported for Apache 2.0 and 1.3. Using patch is preferred over module, because original module has some drawbacks, for example, it breaks graceful restart.
