PRTG Network Monitor remains a top-tier choice for infrastructure visibility, though its recent shift to a subscription-only model
The license key can be purchased directly from Paessler AG or from authorized resellers. The cost of the license depends on the number of sensors ( monitoring points) required. A sensor can be a device, a server, a virtual machine, or a specific aspect of a device (e.g., a network interface). prtg network monitor license key full