Security Gateways: The following information comes from IoT Solutions World Congress 2016 held in Barcelona. One of the conference speakers was Andrew Ginter, VP of Industrial Security at Waterfall Security. The company offers solutions for one-way Security Gateways.
Can they replace firewalls in industrial network environments? They provide absolute protection in the control of business systems and networks from attacks originating from the outside networks.
Unidirectional gates are a technology divided into two parts: there is a TX device that contains a laser, and an RX device that contains an optical receiver. 
Security Gateways pairs can easily transmit information from a business network but prevent multiple viruses, DoS attacks, human error or any information from the protected network.
Waterfall Security software collects real-time data from any work on servers within the protected network. The software transmits the data to the external network, through replica servers containing the data.
Waterfall Security provides capabilities for dozens of replicated industrial applications, including process history, process databases data, systems control of servers, OPC servers, and low-level devices.
Replication solutions are also available for file servers, mail servers, print servers, SIEM servers and other components that are needed to integrate modern networks into business networks.
Η procedure of server-replication is not visible to external users, and has no effect on the original operations of the servers. External users have access to use the replicated servers in the same way they would use the original servers, without changing the work processes.
