The goal of physical security is to keep people out of areas they are not authorized to be in.
This includes restricted areas, control rooms, high-security areas, electrical and network panels, server rooms, and other restricted or sensitive area. If an attacker has physical access to network or computer equipment, it is only a matter of time until he or she gains access to the network or the computer system. The physical defense layer, includes recommendations such as building sufficiently sized walls, applying door locks, installing CCTV cameras, and defining policies and controls to deal with visitors and guests.
