This CISSP practice question tests your understanding of communication and network security. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
An organization wants to ensure that only devices that meet security policies can connect to the network. Which technology should be deployed?
Firewall
Why wrong: Firewall filters traffic but does not enforce device compliance.
SIEM
Why wrong: SIEM collects and analyzes logs.
IDS
Why wrong: Intrusion Detection System monitors for threats.
NAC
NAC controls network access based on device compliance.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
NAC
Network Access Control (NAC) is the correct technology because it enforces security policies by assessing the compliance of devices (e.g., patch level, antivirus status, OS version) before granting network access. NAC can quarantine non-compliant devices, redirect them to a remediation network, or block them entirely, ensuring only authorized and policy-compliant endpoints connect.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
Firewall
Why it's wrong here
Firewall filters traffic but does not enforce device compliance.
SIEM
Why it's wrong here
SIEM collects and analyzes logs.
IDS
Why it's wrong here
Intrusion Detection System monitors for threats.
NAC
Why this is correct
NAC controls network access based on device compliance.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
The trap here is confusing NAC with a firewall or IDS, as candidates often think a firewall's access control lists (ACLs) are sufficient for device compliance, but NAC specifically performs pre-admission posture checking that firewalls cannot do.
Detailed technical explanation
NAC typically operates using protocols like 802.1X for port-based authentication on switches and wireless access points, or via DHCP and ARP inspection for agentless posture assessment. When a device connects, the NAC system evaluates its health (e.g., via a posture agent or scanning) against a policy, and if non-compliant, it can place the device into a VLAN with restricted access or apply ACLs dynamically. In real-world deployments, NAC integrates with Active Directory and patch management tools to automate remediation workflows.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A security team runs a vulnerability scan on a web application and discovers an unpatched SQL injection flaw. The team prioritises remediation by CVSS score — critical flaws are patched within 24 hours, high within 7 days. Questions like this test whether you understand vulnerability management processes, scanning tools, and remediation prioritisation.
What to study next
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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FAQ
Communication and Network Security — This question tests Communication and Network Security — Read the scenario before looking for a memorised answer..
The correct answer is: NAC — Network Access Control (NAC) is the correct technology because it enforces security policies by assessing the compliance of devices (e.g., patch level, antivirus status, OS version) before granting network access. NAC can quarantine non-compliant devices, redirect them to a remediation network, or block them entirely, ensuring only authorized and policy-compliant endpoints connect.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 24, 2026
This CISSP practice question is part of Courseiva's free ISC2 certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the CISSP exam.
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