Unix , ACLs chroot IP Filter, IPSec VPNs, basic IDS No Yes 24 n/a 3 2002- 10-11 FreeBSD Unix , ACLs , MAC chroot , jail , MAC Partitions IPFW2 , IPFilter , PF Yes Yes No 25 3 2006- 10-11 HP-UX Unix , ACLs chroot IPFilter No ? 4 2002-