Network Security

Network security prevents unauthorized access to, misuse of, and disruption of computer networks and the data that travels across them. It is the set of controls — hardware, software, and policy — that keeps network infrastructure trustworthy and traffic confidential, intact, and available.

The useful mental model is layers of defense around data in motion and the devices that move it.

policy → perimeter controls → internal segmentation → endpoint protection → monitoring
    ↑                                                                          ↓
    └──────────────── incident response and continuous improvement ────────────┘

Every network carries traffic between systems that trust each other to varying degrees. Network security decides which traffic is permitted, inspects what flows, detects what deviates from expected behavior, and responds when something goes wrong.

Why network security matters

Every organization depends on network connectivity. Email, file storage, applications, cloud services, industrial control systems, and remote access all rely on networks. An attacker who controls or observes network traffic can steal credentials, exfiltrate data, disrupt services, or pivot deeper into systems.

Network security exists because: