A method of monitoring an Internet-of-Things (IoT) device. An objective is to provide can detection of device malfunction issues, help to prevent hacking attacks and increase the reliability of IoT devices and IoT networks will be solved by monitoring functional behavior of the device; verifying the functional behavior and comparing the functional behavior with defined configuration functional behavior limits of the device; initiating an action by a watchdog associated with the IoT device based on the comparison between the functional behavior and the defined configuration functional behavior limits of the device.