What is Network Security?
Definition
Network security encompasses the technologies, policies, and practices designed to protect the integrity, confidentiality, and availability of network infrastructure and data in transit. It includes firewalls, intrusion detection, network segmentation, and monitoring.
In Depth
Network security forms a critical defense layer that protects data and systems from external attacks and limits the impact of internal compromises through segmentation. Modern network security has evolved beyond traditional perimeter firewalls to include defense-in-depth strategies: Web Application Firewalls (WAFs) for application-layer protection, network segmentation to isolate sensitive systems, VPNs or zero-trust network access (ZTNA) for remote connectivity, intrusion detection and prevention systems (IDS/IPS) for threat monitoring, DNS filtering to block malicious domains, and DDoS protection for availability. In cloud environments, network security is implemented through security groups, network ACLs, VPC configurations, and private endpoints. SOC 2 auditors evaluate network security as part of the Security criterion, reviewing firewall rules, network diagrams, and monitoring capabilities. ISO 27001 addresses network security through multiple Annex A controls. Organizations should maintain current network diagrams, conduct regular firewall rule reviews, and implement network monitoring with alerting for anomalous traffic patterns.
Related Terms
Encryption in Transit
Encryption in transit protects data as it moves between systems, networks, or endpoints by encrypting the communication channel. TLS (Transport Layer Security) is the most common protocol used to secure data in transit over networks.
Zero Trust
Zero Trust is a security model based on the principle that no user, device, or network should be inherently trusted, regardless of location. Every access request must be continuously verified based on identity, device posture, and context before granting access.
Physical Security
Physical security controls protect an organization's facilities, equipment, and physical assets from unauthorized access, theft, damage, and environmental threats. This includes office access controls, server room protections, visitor management, and environmental monitoring.
Vulnerability Management
Vulnerability management is the continuous process of identifying, classifying, prioritizing, remediating, and mitigating security vulnerabilities in systems and software. It includes regular scanning, patch management, and risk-based prioritization.
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