"I have used BigBrother and Nagios for a long time to
troubleshoot network problems, and I was happy with them--until
Zabbix came along. Zabbix is an enterprise-class open source
distributed monitoring solution for servers, network services, and
network devices. It's easier to use and provides more functionality
than Nagios or BigBrother.
"Zabbix is a server-agent type of monitoring software, meaning
you have a Zabbix server where all gathered data is collected, and
a Zabbix agent running on each host..."