TrinityOS is a step-by-step, example-driven HOWTO on building a very functional Linux box with strong security in mind. TrinityOS is well known for its strong packet firewall ruleset, Chrooted and Split DNS (v9 and v8), secured Sendmail (8.x), Linux PPTP, Serial consoles and Reverse TELNET, DHCPd, SSHd, UPSes, system performance tuning, the automated TrinityOS-Security implementation scripts, and much more.
SFI Director is a tool for managing distributed, heterogeneous UNIX Systems. Its functionality includes System Configuration, Application Distribution, NIS and NIS+ Management, User Creation, and Dynamic System Documentation. It is in service at a number of sites, managing networks of 50 to 200+ UNIX nodes, under Linux, Solaris, Digital UNIX, and HP-UX.