Boundary: In the context of system security, a boundary refers to the defined barrier between different security domains, helping to manage and restrict the flow of information. This could be physical, such as the walls of a secured server room, or logical, such as a firewall or other security device that filters network traffic. Properly managed boundaries are crucial in limiting potential attack vectors and containing any damage if a breach does occur. A system’s boundary protection mechanisms should be defined based on the sensitivity of the information it handles and the potential threats it faces.