Given here is a list of available best free and open-source network monitoring tools to help you undertake comprehensive monitoring aside from policy-0based configurations. Nagios Core – It’s a free monitoring and alerting engine Cacti – A complete network graphing solution0 Observium Community – Low-maintenance network monitoring platform Nmap – Free network mapper & security scanner Logic Monitor – A SaaS-based network monitoring platform Zabbix – Open source network monitoring software Obkio – Enterprise network monitoring tools Icinga – Open source network monitoring application Spiceworks – 100% free network monitoring tool NetCrunch – Free network monitoring tool for network administrators