A server and database monitoring platform.
Two-factor authentication system
Collects data about network useage using libpcap.
Batch system monitoring and archiving
Active-probing-based network IDS for wireless networks
Send steganographed text messages to mtr with fake hops in the network
Monitoring your infrastructure for free.
SpiderOak Nagios check
nagios-statd patch for use with python >= 2.6
Organizing the Knowledge of Humanity
Open Source System and Network Monitoring for Linux Desktop
WatchTower is a cloud server monitoring and management tool