Network security is the set of controls that protect communications and manage traffic across internal and external networks. It includes measures such as firewalls, access controls, network segmentation, secure protocols, and monitoring. Segmentation limits which systems can communicate, helping contain intrusions and reduce unnecessary access.
In an attack, criminals may exploit exposed services or use a compromised device to move between systems. Network controls can block unauthorized connections and alert defenders to unusual traffic or lateral movement. Effective defense also depends on linking network logs with endpoint and cloud records, assigning clear ownership, and coordinating incident response; isolated controls may leave gaps in visibility.