JSTUN is a STUN (Simple Traversal of UDP (User Datagram Protocol) through NAT (Network Address Translation)) implementation. STUN provides a means for applications to discover the presence and type of firewalls or NATs between them and the public Internet. In the presence of a NAT, STUN can also be used by applications to learn the public Internet Protocol (IP) address assigned to the NAT.
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.