- A
MAC filtering
Why wrong: MAC filtering is easy to circumvent by spoofing a legitimate MAC address; it does not verify user identity.
- B
802.1X
802.1X uses Extensible Authentication Protocol (EAP) to authenticate devices/users against a central authentication server, enforcing access based on credentials.
- C
Port security with sticky MAC
Why wrong: Port security limits the number of MAC addresses per port but does not authenticate users; it can be bypassed by spoofing.
- D
VLAN hopping prevention
Why wrong: VLAN hopping prevention (e.g., disabling DTP, using native VLAN tagging) secures trunk links but does not authenticate end devices.
Question 333 of 520
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 company wants to prevent unauthorized personal devices from connecting to the corporate wired network. Employees must authenticate using their domain credentials before gaining full network access. Which security measure should be implemented on the switch ports?
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
802.1X is the correct choice because it provides port-based network access control (PNAC) that requires end devices to authenticate using domain credentials (e.g., via RADIUS) before being granted full network access. This ensures that only authorized users, not just authorized devices, can connect to the corporate wired network, meeting the requirement to prevent unauthorized personal devices.
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 is easy to circumvent by spoofing a legitimate MAC address; it does not verify user identity.
When this WOULD be correct
A company wants to restrict network access to only approved devices based on their MAC addresses, without requiring user authentication. The question would specify that device identity, not user credentials, is the access control factor.
- ✓
802.1X
Why this is correct
802.1X uses Extensible Authentication Protocol (EAP) to authenticate devices/users against a central authentication server, enforcing access based on credentials.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Port security with sticky MAC
Why it's wrong here
Port security limits the number of MAC addresses per port but does not authenticate users; it can be bypassed by spoofing.
- ✗
VLAN hopping prevention
Why it's wrong here
VLAN hopping prevention (e.g., disabling DTP, using native VLAN tagging) secures trunk links but does not authenticate end devices.
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.
✓802.1XCorrect answer▾
Why this is correct
802.1X uses Extensible Authentication Protocol (EAP) to authenticate devices/users against a central authentication server, enforcing access based on credentials.
✗MAC filteringWrong answer — click to see why▾
Why this is wrong here
MAC filtering only checks MAC addresses, not user credentials, so it cannot enforce domain authentication. It also does not prevent unauthorized devices if their MAC is spoofed or manually added.
★ When this WOULD be the correct answer
A company wants to restrict network access to only approved devices based on their MAC addresses, without requiring user authentication. The question would specify that device identity, not user credentials, is the access control factor.
Why candidates choose this
Candidates may confuse MAC filtering with port security or assume that controlling device identity is sufficient for authentication, overlooking the requirement for domain credential verification.
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 port security with 802.1X, thinking that locking MAC addresses via sticky MAC provides user-based authentication, but it only controls device identity, not user credentials, and fails to meet the requirement for domain credential authentication.
Detailed technical explanation
How to think about this question
802.1X operates using the Extensible Authentication Protocol (EAP) over LAN (EAPoL), where the supplicant (client) communicates with the authenticator (switch) and the authentication server (RADIUS) validates domain credentials. In a real-world scenario, if a user connects a personal device that does not support 802.1X (e.g., a legacy printer), the switch can be configured to place that port into a guest VLAN with limited access, while domain-joined devices authenticate seamlessly via PEAP or EAP-TLS.
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.
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.
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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 — 802.1X is the correct choice because it provides port-based network access control (PNAC) that requires end devices to authenticate using domain credentials (e.g., via RADIUS) before being granted full network access. This ensures that only authorized users, not just authorized devices, can connect to the corporate wired network, meeting the requirement to prevent unauthorized personal devices.
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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