: Sends real-time notifications via email, push notifications to Android and iOS apps, or HTTP requests to ensure proactive problem-solving.

Deviating significantly from historical baselines calculated by PRTG’s internal metrics engine. Notification Triggers and Channels

: The fundamental monitoring elements. Each sensor tracks one specific metric, such as CPU load, disk space, or ping latency.

While the 21.x branch is now considered a "Previous Version," it remains widely deployed in legacy environments for its stability and specific feature set.

These improvements directly benefited users, making the product more efficient for large deployments and mixed (IT/OT) environments.

Monitoring tools hold keys to your kingdom, as they require administrative access to scan systems. Securing your PRTG 21.0.x installation is paramount.

represents a significant series of updates from Paessler, focusing on enhancing the usability, security, and multi-platform capabilities of their flagship monitoring tool. Released primarily throughout 2021, the 21.x cycle transitioned the software into a more modernized architecture. Key Features and Improvements

Enhanced sensors for monitoring modern cloud-native environments and hybrid setups.

If you are on version 18.x or 19.x, upgrading to requires planning.

: Version 21.4.73 introduced the FortiGate System Statistics sensor as an experimental feature, enabling firewall health monitoring via REST API.

PRTG Network Monitor is a comprehensive network monitoring solution developed by Paessler AG, a German-based company with over 20 years of experience in the field of network monitoring. PRTG is designed to monitor and analyze the performance and availability of network devices, servers, applications, and services in real-time. The solution uses a combination of SNMP, WMI, and other protocols to collect data from network devices and provides a web-based interface for configuring, monitoring, and analyzing the data.

NetFlow (v5/v9), IPFIX, sFlow, and jFlow for deep packet and traffic analysis. 3. System Requirements and Sizing Guidelines