Zabbix - Track, record, alert and visualize performance and availability of IT resources
TinyWall - Lightweight and non-intrusive firewall
Datadog - See metrics from all of your apps, tools & services in one place with Datadog's cloud monitoring as a service solution. Try it for free.
Windows 10 Firewall Control - Windows 10 Firewall Control: simple and exhaustive solution for applications network activity controlling and monitoring.
Prometheus - An open-source systems monitoring and alerting toolkit.
GlassWire - Visualize network activity in detail, get notified when new apps access the network, look out for...