Hardened Debian improves Debian GNU/Linux with high security and hardening features, hardened kernels and packages, DHKP, and other security related enhancements. It makes systems more difficult to compromise using common attacks such as race conditions, chroot jail escapes, and buffer overflows.
Nagios is a host, service, and network monitoring system that will watch your network and alert you to problems before your clients or end-users do. The system runs checks on hosts and services that you specify using plugins that return status information to Nagios. When problems are encountered, the system will send notifications to system administrators so that they can take action on the problem. The JumpBox for Nagios gives you a head start to using the system. It eliminates the complexity involved in getting the application installed, and allows you to focus on the configuration for your specific environment. Since Nagios is based on plugins, depending on what you want to do this will vary in complexity.