Critical infrastructure systems are frequently constructed with components never designed for use in today's networked environment. While security conscious enterprises have extensive security mechanisms, these do not immediately transfer to many of our critical infrastructure networks. And yet we still need to move data in and out of them safely. This talk examines how to use the computer science concept of state to provide the equivalent of system isolation from hostile traffic on the network. Forget firewalls, air-gaps, and VPNs, and learn to embrace state transfers. This talk will explore the use of state transfer as a safer alternative to network data transfers. As more and more of our critical infrastructure is using TCP/IP networking and being connected via the Internet, methods to isolate the systems from a traffic signal point of view offer the best current technology to protect our networks, both operational technology (OT) and IT. This talk will give real world examples showing how to maintain all desired functionality, and yet sever the connection to unwanted signals carried in network traffic.