Prtg Network | Monitor 21.0.x
Title: The Silent Disk – A PRTG 21.0.x Recovery Story
Context:
Sophia managed the network for a mid-sized logistics company. Her PRTG core server (v21.0.68) ran on Windows Server 2019 with a local PostgreSQL database. One Monday morning, she noticed that all sensors on a critical file server showed “Unknown” status. The PRTG web interface was slow, and sensor updates had frozen.
Simon opened the SSH Remote Execution Sensor he had custom-scripted months ago. It was a hidden gem in his setup. While PRTG checked if the server was awake, this script logged in and checked if the server was actually thinking. prtg network monitor 21.0.x
- ✔ Use PRTG Administration Tool for service control, not Windows Services alone.
- ✔ Monitor the Probe Health Sensor – critical in 21.0.x.
- ✔ Set up automatic database check weekly.
- ✔ Avoid mixing v21 with very old custom EXE sensors (they can stall the probe queue).
- ✔ If possible, plan upgrade to 23.x or 24.x – but if staying on 21.0.x, apply 21.0.71.
Quarterly Tasks
- Update remote probes individually (if core stays on 21.0.x, probes can remain too)
- Test failover cluster by manually shutting down the master node
- Audit user accounts – Remove technicians who left the org
- Renew SSL certificates for the PRTG web server (port 443)
- You rely on old Python 2.7 custom scripts
- Your hardware is pre-2019 and cannot run Windows Server 2022
- You have a closed air-gapped network with no need for new features
- Your PRTG license is perpetual (no maintenance) – newer versions require active maintenance