- A
Supplicant
Why wrong: The supplicant is the client software on the user’s device that requests access, it does not enforce policy.
- B
Authenticator
The authenticator (e.g., a switch) enforces the policy by controlling the port state based on the authentication result.
- C
Authentication server
Why wrong: The authentication server (e.g., RADIUS) validates credentials and sends authorization instructions, but enforcement is done by the authenticator.
- D
Policy server
Why wrong: The policy server defines and manages policies, but does not enforce them at the network level.
Question 144 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 implement network access control that requires users to authenticate before gaining access to the network. The NAC solution uses a policy that checks for antivirus updates and OS patches. Which component enforces the policy?
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
✓
Authenticator
The Authenticator (typically a switch or wireless access point) is the component that enforces the NAC policy by controlling access to the network port or SSID. It receives the authentication result from the Authentication Server and applies the policy (e.g., placing the endpoint in a quarantine VLAN if antivirus or OS patch checks fail). This enforcement is defined in IEEE 802.1X, where the Authenticator acts as the gatekeeper between the Supplicant and the network.
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.
- ✗
Supplicant
Why it's wrong here
The supplicant is the client software on the user’s device that requests access, it does not enforce policy.
When this WOULD be correct
In a question asking 'Which component requests network access and provides credentials?', the supplicant would be correct, as it is the client-side entity that initiates authentication.
- ✓
Authenticator
Why this is correct
The authenticator (e.g., a switch) enforces the policy by controlling the port state based on the authentication result.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Authentication server
Why it's wrong here
The authentication server (e.g., RADIUS) validates credentials and sends authorization instructions, but enforcement is done by the authenticator.
When this WOULD be correct
In a scenario where the question asks which component stores and evaluates the access policies (e.g., 'Which component defines the rules for network access?'), the authentication server or policy server would be correct.
- ✗
Policy server
Why it's wrong here
The policy server defines and manages policies, but does not enforce them at the network level.
When this WOULD be correct
A question asking 'Which component stores and manages the NAC policies?' or 'Which component defines the access rules based on endpoint compliance?' would make the policy server the correct answer.
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.
✓AuthenticatorCorrect answer▾
Why this is correct
The authenticator (e.g., a switch) enforces the policy by controlling the port state based on the authentication result.
✗SupplicantWrong answer — click to see why▾
Why this is wrong here
The supplicant is the client software that requests access, not the component that enforces the policy. Enforcement is done by the authenticator (e.g., switch or wireless controller) which applies the policy after authentication.
★ When this WOULD be the correct answer
In a question asking 'Which component requests network access and provides credentials?', the supplicant would be correct, as it is the client-side entity that initiates authentication.
Why candidates choose this
Candidates may confuse the supplicant's role in authentication with policy enforcement, thinking the client-side software enforces the checks, when in fact it only reports its status.
✗Authentication serverWrong answer — click to see why▾
Why this is wrong here
The authentication server (e.g., RADIUS) validates credentials and checks policy compliance but does not enforce the policy by controlling network access; enforcement is done by the authenticator (e.g., switch or wireless controller) that applies the result.
★ When this WOULD be the correct answer
In a scenario where the question asks which component stores and evaluates the access policies (e.g., 'Which component defines the rules for network access?'), the authentication server or policy server would be correct.
Why candidates choose this
Candidates often confuse the authentication server's role in validating credentials and policies with the enforcement action, assuming the server that checks compliance also enforces access.
✗Policy serverWrong answer — click to see why▾
Why this is wrong here
The policy server defines and stores policies but does not enforce them; enforcement is done by the authenticator (e.g., switch or wireless controller) that applies the policy to the endpoint.
★ When this WOULD be the correct answer
A question asking 'Which component stores and manages the NAC policies?' or 'Which component defines the access rules based on endpoint compliance?' would make the policy server the correct answer.
Why candidates choose this
Candidates confuse the role of the policy server with enforcement because the term 'policy' implies control, leading them to think it enforces the rules it defines.
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 the Authentication Server (which makes the decision) with the Authenticator (which enforces the decision), especially when the question emphasizes 'policy checks' like antivirus updates, leading them to incorrectly select the server.
Detailed technical explanation
How to think about this question
Under the hood, the Authenticator (switch/AP) uses EAP over LAN (EAPoL) to communicate with the Supplicant and forwards EAP messages to the RADIUS server. After the server evaluates posture via CoA (Change of Authorization) or RADIUS attributes like Filter-ID, the Authenticator dynamically applies a VLAN assignment or ACL to enforce the policy. In a real-world scenario, if the Authenticator fails to enforce, a non-compliant device could bypass quarantine and access sensitive resources, making the Authenticator's role critical.
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 help-desk technician troubleshoots why a newly connected PC cannot reach shared printers on the same floor. The cable is good, the switch port is active, but the PC is in VLAN 20 and the printers are in VLAN 10. The uplink trunk only allows VLAN 10. A trunk being up does not mean every VLAN crosses it.
Visual reference
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
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
- →
Network Security — study guide chapter
Learn the concepts, then practise the questions
- →
Network Security practice questions
Targeted practice on this topic area only
- →
All N10-009 questions
520 questions across all exam domains
- →
CompTIA Network+ N10-009 study guide
Full concept coverage aligned to exam objectives
- →
N10-009 practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Related N10-009 practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Networking Concepts practice questions
Practise N10-009 questions linked to Networking Concepts.
Network Implementation practice questions
Practise N10-009 questions linked to Network Implementation.
Network Operations practice questions
Practise N10-009 questions linked to Network Operations.
Network Security practice questions
Practise N10-009 questions linked to Network Security.
Network Troubleshooting practice questions
Practise N10-009 questions linked to Network Troubleshooting.
Network+ network fundamentals practice questions
Practise N10-009 questions linked to Network+ network fundamentals.
Practice this exam
Start a free N10-009 practice session
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
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: Authenticator — The Authenticator (typically a switch or wireless access point) is the component that enforces the NAC policy by controlling access to the network port or SSID. It receives the authentication result from the Authentication Server and applies the policy (e.g., placing the endpoint in a quarantine VLAN if antivirus or OS patch checks fail). This enforcement is defined in IEEE 802.1X, where the Authenticator acts as the gatekeeper between the Supplicant and the network.
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 →
Keep practising
More N10-009 practice questions
- Which of the following network devices operates primarily at Layer 2 of the OSI model and uses MAC addresses to forward…
- Which of the following is a characteristic of UDP when compared to TCP?
- Which of the following IPv6 addresses is a valid link-local address?
- Which of the following security mechanisms requires a user to authenticate before gaining access to the wired network at…
- Which of the following network protocols operates at the Transport layer of the OSI model and provides connection-orient…
- Which of the following is a characteristic of a connectionless protocol at the transport layer?
Last reviewed: Jun 11, 2026
This N10-009 practice question is part of Courseiva's free CompTIA 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 N10-009 exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.