PRTG Network MonitorScreenshot
An advanced, easy-to-use network monitoring solution. Features include: up/downtime monitoring, traffic and usage monitoring, instant alerts, analysis and reporting, failover clustering.Users can monitor their networks using more than 80 sensor types (e.g. SNMP, WMI, packet sniffing, NetFlow, PING, HTTP, FTP, VMware, SSH, VoIP, etc.) PRTG Network Monitor is available in both Freeware and Commercial editions. No add-ons or extras needed.