The Industrial Internet of Things, or IIoT, refers to the application of instrumentation and connected sensors and other devices to machinery and vehicles in the transport, energy, and other critical infrastructure sectors. In the energy sector, distributed energy resources (DERs) such as solar photovoltaics and wind turbines include sensors, data transfer and communications systems, instruments, and other commercially available devices that are networked together. DERs introduce information exchanges between a utility’s distribution control system and the DERs to manage the flow of energy in the distribution grid.  This practice guide explores how information exchanges among commercial- and utility-scale DERs and electric distribution grid operations can be monitored and protected from certain cybersecurity threats and vulnerabilities.  The NCCoE built a reference architecture using commercially available products to show organizations how several cybersecurity capabilities, including...