CISSP Domain 4 study guide
What Communication and Network Security tests
Domain 4 is a traffic-flow and trust-boundary domain. The exam asks you to select architectures, components, and protected communication channels that reduce exposure while meeting availability and business requirements.
Domain 4 objectives
Use these official objective areas as a coverage checklist, then combine them in scenario practice.
Secure network architecture
Apply segmentation, zero trust, defense in depth, resilient design, and secure protocol principles.
Secure network components
Assess switches, routers, firewalls, endpoints, wireless systems, transmission media, and network access control.
Secure communication channels
Select voice, video, remote access, virtualized, third-party, and data-communication protections.
High-yield distinctions
Segmentation
Limits communication and constrains lateral movement between trust zones.
Microsegmentation
Applies fine-grained policy around workloads or identities.
TLS
Protects application sessions over a transport connection.
IPsec
Protects IP traffic in transport or tunnel mode.
IDS
Detects and alerts on suspicious activity.
IPS
Operates inline and can actively block traffic.
Common exam trap
Choose the architecture before the appliance. A properly defined trust boundary or segmented design often solves the root problem better than another point product.
How to study Domain 4
Step 1: Trace traffic through the OSI and TCP/IP models.
Step 2: Map protocols to their protections and weaknesses.
Step 3: Design zones and trust boundaries.
Step 4: Compare secure remote-access options.
Step 5: Practice availability and resilience scenarios.