- A
MAC filtering
Why wrong: MAC filtering only checks the hardware address of the device, not the user. It does not authenticate users with domain credentials and can be bypassed by MAC spoofing.
- B
802.1X with EAP-TLS
802.1X with EAP-TLS provides user authentication using certificates, typically tied to domain credentials. It ensures that only authenticated users can gain access to the network, and it can be integrated with Active Directory.
- C
WPA2-PSK
Why wrong: WPA2-PSK is a wireless security method that uses a pre-shared key. It is not suitable for wired networks and does not authenticate individual users with domain credentials.
- D
Port security
Why wrong: Port security limits the number of MAC addresses on a switch port or restricts specific MACs, but it does not authenticate users. It can be used as a supplement but not for domain-based user authentication.
Quick Answer
The correct answer is 802.1X with EAP-TLS because it enforces port-based network access control, requiring each user to authenticate with domain credentials through a RADIUS server before the switch port opens for traffic. EAP-TLS provides mutual authentication using digital certificates, ensuring that both the user device and the network verify each other’s identity, which is essential for securing wired connections against unauthorized access. On the CompTIA Network+ N10-009 exam, this scenario tests your understanding of how 802.1X integrates with RADIUS and EAP-TLS to meet enterprise authentication requirements; a common trap is choosing MAC filtering or PSK, which lack per-user credential validation. Remember the memory tip: “TLS for TLS” — Transport Layer Security requires certificates on both sides, so EAP-TLS is the only option that uses mutual certificate-based authentication for domain-joined devices.
N10-009 Network Security Practice Question
This N10-009 practice question tests your understanding of network security. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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 network administrator needs to ensure that only authorized devices can connect to the wired network. Each user must authenticate using their domain credentials. Which of the following should be implemented?
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
802.1X with EAP-TLS
802.1X with EAP-TLS is correct because it provides port-based network access control that requires each user to authenticate using their domain credentials (via a RADIUS server) before the switch port is opened for traffic. EAP-TLS uses mutual authentication with digital certificates, ensuring only authorized devices and users gain access to the wired 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.
- ✗
MAC filtering
Why it's wrong here
MAC filtering only checks the hardware address of the device, not the user. It does not authenticate users with domain credentials and can be bypassed by MAC spoofing.
- ✓
802.1X with EAP-TLS
Why this is correct
802.1X with EAP-TLS provides user authentication using certificates, typically tied to domain credentials. It ensures that only authenticated users can gain access to the network, and it can be integrated with Active Directory.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
WPA2-PSK
Why it's wrong here
WPA2-PSK is a wireless security method that uses a pre-shared key. It is not suitable for wired networks and does not authenticate individual users with domain credentials.
- ✗
Port security
Why it's wrong here
Port security limits the number of MAC addresses on a switch port or restricts specific MACs, but it does not authenticate users. It can be used as a supplement but not for domain-based user authentication.
Common exam traps
Common exam trap: answer the scenario, not the keyword
CompTIA often tests the distinction between port security (which is MAC-based and does not authenticate users) and 802.1X (which provides user authentication via RADIUS), leading candidates to mistakenly choose port security when the question explicitly requires domain credential authentication.
Detailed technical explanation
How to think about this question
802.1X operates at the data link layer, using EAP over LAN (EAPoL) to encapsulate authentication messages between the supplicant (client) and the authenticator (switch), which forwards them to a RADIUS server. EAP-TLS requires both client and server certificates, providing strong mutual authentication and resistance to man-in-the-middle attacks; the RADIUS server typically integrates with Active Directory to validate domain credentials. In a real-world scenario, a misconfigured switch might fail to place the port into an unauthorized state if the RADIUS server is unreachable, causing a fallback to an open port unless the 'dynamic VLAN assignment' or 'guest VLAN' is properly set.
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 junior network technician can log in to a core router but cannot reach the enable prompt or configuration mode. The AAA server is authenticating the login — but the authorisation policy only grants privilege level 1, not 15. Authentication (who you are) is working; authorisation (what you can do) is not.
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.
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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: 802.1X with EAP-TLS — 802.1X with EAP-TLS is correct because it provides port-based network access control that requires each user to authenticate using their domain credentials (via a RADIUS server) before the switch port is opened for traffic. EAP-TLS uses mutual authentication with digital certificates, ensuring only authorized devices and users gain access to the wired 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 →
Same concept, more angles
2 more ways this is tested on N10-009
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A network administrator wants to prevent unauthorized devices from connecting to the network through a switch port. Which security feature should be enabled on the switch?
medium- ✓ A.802.1X
- B.Port security
- C.MAC filtering
- D.Storm control
Why A: 802.1X is the correct answer because it provides port-based network access control (PNAC) that authenticates devices before granting network access. It uses the Extensible Authentication Protocol (EAP) over LAN (EAPoL) to communicate with a RADIUS server, ensuring only authorized users or devices can connect through the switch port. This prevents unauthorized devices from accessing the network at Layer 2, regardless of MAC address or IP configuration.
Variation 2. A network administrator wants to prevent unauthorized devices from connecting to the company's Ethernet ports. The company uses a centralized authentication server. Which IEEE standard should be implemented?
medium- ✓ A.802.1X
- B.802.11i
- C.802.3af
- D.802.1Q
Why A: 802.1X is the IEEE standard for port-based Network Access Control (NAC) that authenticates devices before granting access to an Ethernet port. It uses a centralized authentication server (typically RADIUS) to verify credentials, preventing unauthorized devices from connecting to the network. This directly matches the requirement of controlling access at the port level with a centralized server.
Last reviewed: Jun 30, 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.
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