VoIP SIP and SKINNY quality analyzer and packet / audio recording tool
Light-weight system monitor for X
An eye on your system
Xymon monitors your hosts, your network services, and everything else.
Disk Inspection and Monitoring
Nagios network monitoring software is enterprise server monitoring
Linux performance monitoring on-screen or to CSV file
Monitors a number of web pages for changes.
Pure Java Network Tools
Monitor or control the progress of data through a pipe
Monitor and control your home and several energy sources
JENNOM - Java Enterprise Network Nodes Monitor
Java Job Scheduling and Task Automation
OpenDDS is open source publish/subscribe middleware
Logging utility for DB2 for LUW written in SQL-PL
Enterprise-class, distributed monitoring solution for networks & apps
Monitorix is a system monitoring tool
Desktop Independent Power Manager
Continuously monitor server connections