Communication module with network isolation and communication filter

Abstract

Aspects of the invention provide apparatuses, systems, and computer readable media for protecting a programmable logic controller (PLC)and plant networkagainst unauthorized access and for providing robust intended communication. A communication moduleprovides only intended communication and blocks all unintended communication between the plant network and a control network/office networkwithout using external infrastructure network devices. The communication module includes an Ethernet switchand ports that electrically couple the CPU module, a plant network, and control/office network and controls communication to the PLC and the plant network from the control/office network by forwarding packets based on configuration informationand, where the packets are received through the ports. The communication module passes packets only when the associated source address and destination address are in accordance with the configuration information. The communication module may further pass packets based on packet traffic limits.