Nagios Nagios is an open source monitoring systems that keeps an eye on your network, hosts and even services using plug-ins and SNMP. It's web-based user interface allow you to quickly discover problems...
OpenNMS 1.6 OpenNMS is an open source enterprise-grade network management platform. OpenNMS will monitor both service and the hosts they run on and inform you of any errors and provide statistical information...
Nagios 
