"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..."