Network security is often discussed in terms of firewalls, encryption algorithms, IPS signatures, and authentication technologies. Yet all of these tools share a common weakness: no one can protect systems if an attacker is able to physically access the equipment. A single open door, a distracted employee, or an unmonitored server room can undermine even the most sophisticated security design. Physical security is the first and most fundamental layer of defense. Without it, confidentiality, integrity, and availability cannot be guaranteed—and forensic evidence cannot be preserved when something goes wrong.