If you hit 101 sensors, PRTG does not shut down. It simply disables random sensors until you drop back to 100. You never lose data or access. | Myth | Truth | |------|-------| | "I can use a keygen to get sensors forever." | Keygens are malware. Paessler’s server-side validation prevents offline activation hacks. | | "The license key is stored in the registry; I can share it." | Keys are bound to your installation ID. Sharing invalidates both copies. | | "PRTG free version is just a trial." | False. Free version is permanent and fully functional at 100 sensors. | | "I need a key to update PRTG." | Updates require a valid paid license or the free version (no key needed). | | "Educational keys work for commercial use." | No. Paessler audits and will deactivate keys used improperly. | Part 7: Alternatives to Buying a PRTG Key If you truly need more than 100 sensors but cannot afford PRTG, consider these open-source alternatives (no license keys required):

Do not fall for cracked versions, keygens, or YouTube videos promising free unlimited keys. They are traps—for your security, your career, and your organization’s legal standing.

| Tool | Sensor/Device Limit | Learning Curve | |------|---------------------|----------------| | Zabbix | Unlimited (NB: each check counts as an "item") | High | | Checkmk Raw | Up to 750 services free | Medium | | LibreNMS | Unlimited (uses SNMP) | Medium | | Nagios Core | Unlimited | High | | Prometheus + Grafana | Unlimited | High |