Prtg Network Monitor 21.0.x -

Sensors are the "eyes" of PRTG. In the 21.0.x updates, Paessler optimized several key sensors:

The 21.0.x release cycle added several native sensors that previously required custom scripts or third-party plugins:

Alerting and Notifications

In previous versions, cluster nodes sometimes suffered from synchronization lags, leading to false "down" alerts during failover testing. Version 21.0.x hardened the database replication protocol, ensuring that configuration changes (like adding a sensor or modifying a threshold) replicated within seconds across all nodes in a cluster.

If you already run IIS (Internet Information Services) on port 80/443, PRTG’s web server fails.