The explosive growth in networks, connectivity, and communications has paved the way for the unprecedented shift in business, personal, and government services into electronic, web-enabled forms. This growth in e-business and e-commerce greatly expanded the threat surface that fraudsters, criminals, unscrupulous business competitors, nation states, and non–nation-state actors can use to take harmful actions against others around the world. For several decades, the world has operated on what is nearly a network monoculture: one set of protocols and standards is used to power most of the internet, e-commerce, and e-business. These standards are known as ISO’s Open Systems Interconnection (OSI) 7-Layer reference Model and the Internet Engineering Task Force’s (IETF) Transmission Control Protocol over Internet Protocol (TCP/IP1) model are used to describe and inform the actual implementation of the required protocols used by almost every laptop, smartphone, smart house, and smart car to communicate with servers and applications in businesses and governments. These models or protocol stacks, therefore, become our map of the threat surface. Security professionals must have a solid practical knowledge and understanding of modern networking and internetworking concepts, techniques, technologies, and security issues. Their work is like that of a police officer patrolling a neighborhood in that they must understand how things are laid out and how the architectural features of the built environment may affect the ability of people to live and work in the area—how it can make their lives safer and more convenient, or how it can provide opportunities for crime or for accidental mishaps. Security professionals also need to have knowledge of the best ways to keep the “neighborhood” (i.e., the computer environment) secure and able to defend against attacks. The need for such a policing mindset is especially acute in systems for building automation, computer-directed manufacturing, and shipping and logistics facilities where many companies have limited or no remote visibility into their operational technology systems. This course includes an orientation to the network neighborhood via the OSI 7-Layer and TCP/IP models in the context of internetworking and communications. It also probes each of the seven layers of this combined protocol stack, introducing the key technologies at each layer and their normal uses. There is also information on various protocols that run on top of this architecture, as well as attack and defensive strategies and tactics. Additionally, discussed in this course is how to manage network security and secure wireless communications.