A smart process control switch can implement a lockdown routine to lockdown its communication ports exclusively for use by devices having known physical addresses, enabling the smart process control switch to prevent new, potentially hostile, devices from communicating with other devices to which the smart process control switch is connected. Further, the smart process control switch can implement an address mapping routine to identify “known pairs” of physical and network addresses for each device communicating via a port of the smart process control switch. Thus, even if a new hostile device is able to spoof a known physical address in an attempt to bypass locked ports, the smart process control switch can detect the hostile device by checking the network address of the hostile device against the expected network address for the “known pair.”