- A
Port security
Why wrong: Port security limits the number of MAC addresses allowed on a port but does not authenticate users or devices.
- B
802.1X
802.1X provides port-based authentication using EAP and requires credentials from the device or user.
- C
VLAN hopping
Why wrong: VLAN hopping is an attack technique, not a security control.
- D
DHCP snooping
Why wrong: DHCP snooping filters DHCP messages and prevents rogue DHCP servers, but does not authenticate devices.
Question 337 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 security auditor recommends implementing a solution that authenticates users and devices before granting network access, regardless of the physical port they connect to. Which technology should be deployed?
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 technology because it provides port-based network access control (PNAC) that authenticates users and devices before granting network access, regardless of the physical port they connect to. It uses the Extensible Authentication Protocol (EAP) over LAN (EAPoL) to communicate with a RADIUS server, ensuring that only authenticated endpoints are allowed on the network. This meets the auditor's requirement for authentication at the port level, independent of the switch port used.
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.
- ✗
Port security
Why it's wrong here
Port security limits the number of MAC addresses allowed on a port but does not authenticate users or devices.
When this WOULD be correct
A question asks: 'Which feature prevents unauthorized devices from connecting to a switch by limiting the number of MAC addresses per port?' Then port security would be correct.
- ✓
802.1X
Why this is correct
802.1X provides port-based authentication using EAP and requires credentials from the device or user.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
VLAN hopping
- ✗
DHCP snooping
Why it's wrong here
DHCP snooping filters DHCP messages and prevents rogue DHCP servers, but does not authenticate devices.
When this WOULD be correct
A question asks: 'Which technology prevents unauthorized DHCP servers from assigning IP addresses on a network?' In that context, DHCP snooping is 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.
✓802.1XCorrect answer▾
Why this is correct
802.1X provides port-based authentication using EAP and requires credentials from the device or user.
✗Port securityWrong answer — click to see why▾
Why this is wrong here
Port security limits MAC addresses per port but does not authenticate users or devices before granting network access; it only controls which MAC addresses are allowed on a specific switch port.
★ When this WOULD be the correct answer
A question asks: 'Which feature prevents unauthorized devices from connecting to a switch by limiting the number of MAC addresses per port?' Then port security would be correct.
Why candidates choose this
Candidates confuse port security with network access control because both deal with restricting device connections, but port security lacks authentication and is port-specific.
✗VLAN hoppingWrong answer — click to see why▾
Why this is wrong here
VLAN hopping is an attack technique, not a security solution. It exploits switch configuration to gain unauthorized access to VLANs, whereas the question asks for a technology that authenticates users and devices before granting network access.
★ When this WOULD be the correct answer
A question asking 'Which attack allows a device to access traffic from a different VLAN by manipulating trunking protocols?' would have VLAN hopping as the correct answer.
Why candidates choose this
Candidates may confuse VLAN hopping with a security mechanism because it involves network access control at the VLAN level, but it is actually a vulnerability, not a solution.
✗DHCP snoopingWrong answer — click to see why▾
Why this is wrong here
DHCP snooping is a security feature that filters untrusted DHCP messages to prevent rogue DHCP servers, but it does not authenticate users or devices before granting network access.
★ When this WOULD be the correct answer
A question asks: 'Which technology prevents unauthorized DHCP servers from assigning IP addresses on a network?' In that context, DHCP snooping is the correct answer.
Why candidates choose this
Candidates may confuse DHCP snooping with network access control because both involve security at the switch level, leading them to think it can authenticate users.
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 because both control port access, but port security only filters by MAC address and does not provide user authentication or integration with a central authentication server, which is the key requirement in the question.
Detailed technical explanation
How to think about this question
802.1X operates in three roles: supplicant (client), authenticator (switch/AP), and authentication server (RADIUS). The authenticator initially places the port in an unauthorized state, allowing only EAPoL traffic; only after successful authentication does the port transition to an authorized state, dynamically assigning the client to a specific VLAN or ACL. In real-world deployments, 802.1X is often combined with MAC Authentication Bypass (MAB) for devices that do not support 802.1X, such as printers or IoT sensors, to maintain security without breaking legacy device connectivity.
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.
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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 technology because it provides port-based network access control (PNAC) that authenticates users and devices before granting network access, regardless of the physical port they connect to. It uses the Extensible Authentication Protocol (EAP) over LAN (EAPoL) to communicate with a RADIUS server, ensuring that only authenticated endpoints are allowed on the network. This meets the auditor's requirement for authentication at the port level, independent of the switch port used.
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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