http://www.zabbix.com/
Abbix (Z?bix) is an enterprise-class open source solution that provides distributed system monitoring and network monitoring capabilities based on a web interface.
Zabbix can monitor various network parameters, ensure the safe operation of the server system, and provide a flexible notification mechanism to enable system administrators to quickly locate/resolve various problems.
Zabbix consists of 2 parts, Zabbix server and optional Components Zabbix agent.
Zabbix server can be used Snmp,zabbix agent,ping, port monitoring and other methods to provide remote server/network status monitoring, data collection and other functions, it can run in Linux,solaris,hp-ux,aix,free BSD, Open Bsd,os x and other platforms.
zabbix-Enterprise-Class open source solution that provides distributed system monitoring and network monitoring capabilities based on a web interface