- A
VPN
Why wrong: A VPN encrypts traffic between a client and network but does not enforce device compliance policies. It assumes the device is already trusted.
- B
Network Access Control (NAC)
NAC solutions like Cisco ISE or Aruba ClearPass can enforce security policies by scanning endpoints before allowing access and quarantining non-compliant devices.
- C
Access control list (ACL)
Why wrong: ACLs filter traffic based on packet attributes but do not evaluate device health or compliance. They are stateless and cannot enforce pre-admission policies.
- D
Intrusion prevention system (IPS)
Why wrong: An IPS monitors and blocks malicious traffic but does not perform endpoint compliance checks before granting network access.
Question 155 of 520
N10-009 Network Security Practice Question
This N10-009 practice question tests your understanding of 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.
A company wants to ensure that only authorized devices that comply with security policies (such as updated antivirus and OS patches) are allowed to connect to the internal network. Both wired and wireless connections are used. Which of the following security solutions would best enforce this requirement?
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Network Access Control (NAC)
Network Access Control (NAC) is the correct solution because it enforces security policies by inspecting the health and compliance of devices—such as checking for updated antivirus definitions and OS patches—before granting access to the network. NAC can operate on both wired (e.g., 802.1X) and wireless (e.g., WPA2-Enterprise with RADIUS) connections, blocking or quarantining non-compliant devices. This matches the requirement to ensure only authorized, policy-compliant devices connect.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
VPN
Why it's wrong here
A VPN encrypts traffic between a client and network but does not enforce device compliance policies. It assumes the device is already trusted.
When this WOULD be correct
A company needs to allow remote employees to securely access internal resources over the internet. VPN would be correct when the requirement is encrypted remote connectivity, not device compliance enforcement.
- ✓
Network Access Control (NAC)
Why this is correct
NAC solutions like Cisco ISE or Aruba ClearPass can enforce security policies by scanning endpoints before allowing access and quarantining non-compliant devices.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Access control list (ACL)
Why it's wrong here
ACLs filter traffic based on packet attributes but do not evaluate device health or compliance. They are stateless and cannot enforce pre-admission policies.
- ✗
Intrusion prevention system (IPS)
Why it's wrong here
An IPS monitors and blocks malicious traffic but does not perform endpoint compliance checks before granting network access.
When this WOULD be correct
A company needs to monitor network traffic in real-time and automatically block malicious activities, such as exploit attempts or malware propagation, without requiring endpoint compliance checks.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The N10-009 exam frequently reuses these exact scenarios with slightly different constraints.
✓Network Access Control (NAC)Correct answer▾
Why this is correct
NAC solutions like Cisco ISE or Aruba ClearPass can enforce security policies by scanning endpoints before allowing access and quarantining non-compliant devices.
✗VPNWrong answer — click to see why▾
Why this is wrong here
VPN creates encrypted tunnels for remote access but does not enforce endpoint compliance checks (e.g., antivirus status, OS patches) before granting network access. It only secures data in transit, not device authorization.
★ When this WOULD be the correct answer
A company needs to allow remote employees to securely access internal resources over the internet. VPN would be correct when the requirement is encrypted remote connectivity, not device compliance enforcement.
Why candidates choose this
Candidates confuse VPN's role in secure remote access with NAC's device compliance enforcement, assuming VPN can also verify endpoint security posture.
✗Access control list (ACL)Wrong answer — click to see why▾
Why this is wrong here
ACLs filter traffic based on IP addresses or ports but cannot assess device compliance (e.g., antivirus status, OS patches) before granting network access.
★ When this WOULD be the correct answer
An ACL would be correct if the requirement were to restrict traffic between specific network segments (e.g., block all traffic from the guest VLAN to the internal server subnet) based on IP addresses or protocols.
Why candidates choose this
Candidates may confuse ACLs with NAC because both can control network access, but ACLs lack the endpoint posture assessment needed for compliance enforcement.
✗Intrusion prevention system (IPS)Wrong answer — click to see why▾
Why this is wrong here
An IPS is designed to detect and block malicious traffic, not to enforce device compliance or control network access based on security posture.
★ When this WOULD be the correct answer
A company needs to monitor network traffic in real-time and automatically block malicious activities, such as exploit attempts or malware propagation, without requiring endpoint compliance checks.
Why candidates choose this
Candidates may confuse IPS with NAC because both involve security enforcement, but IPS focuses on threat detection rather than access control based on device health.
Analysis generated from the official N10-009blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse NAC with VPN or ACL, thinking VPN provides endpoint security or ACLs can enforce policy compliance, but NAC is the only solution that performs dynamic, policy-based admission control based on device health and authorization.
Detailed technical explanation
How to think about this question
NAC typically uses the 802.1X standard with EAP (e.g., EAP-TLS or PEAP) and a RADIUS server (like Cisco ISE or Aruba ClearPass) to authenticate and assess device posture via agents or passive scanning. Posture validation can involve checking registry keys, file versions, or running processes (e.g., verifying antivirus definitions via OPSWAT or custom scripts), and non-compliant devices are placed into a quarantine VLAN with restricted access. In real-world deployments, NAC can also integrate with MDM solutions to enforce policies on mobile devices, and it supports pre-admission and post-admission controls to continuously monitor compliance.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A security administrator must allow nursing staff to reach a patient records server while blocking access from the guest Wi-Fi VLAN. After applying an extended ACL, traffic is still blocked from nursing workstations. The ACL was applied outbound instead of inbound on the wrong interface. Questions like this test ACL direction and placement rules.
Quick reference
AAA Protocol Comparison
| Protocol | Port(s) | Encryption | Transport | Primary Use |
|---|---|---|---|---|
| RADIUS | 1812 / 1813 | Password only | UDP | Network access control |
| TACACS+ | 49 | Full packet | TCP | Device administration |
| Diameter | 3868 | Full session | TCP / SCTP | Carrier / mobile networks |
| 802.1X | — | EAP-based | Layer 2 | Port-based access control |
TACACS+ encrypts the entire packet; RADIUS only encrypts the password field — a key exam distinction.
What to study next
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FAQ
Questions learners often ask
What does this N10-009 question test?
Network Security — This question tests Network Security — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Network Access Control (NAC) — Network Access Control (NAC) is the correct solution because it enforces security policies by inspecting the health and compliance of devices—such as checking for updated antivirus definitions and OS patches—before granting access to the network. NAC can operate on both wired (e.g., 802.1X) and wireless (e.g., WPA2-Enterprise with RADIUS) connections, blocking or quarantining non-compliant devices. This matches the requirement to ensure only authorized, policy-compliant devices connect.
What should I do if I get this N10-009 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
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Last reviewed: Jun 11, 2026
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