- A
802.1X
Why wrong: 802.1X requires authentication via a RADIUS server, but it does not rely on a static list of MAC addresses. It is not the best choice for simply restricting access by MAC address.
- B
Port security
Port security allows the administrator to configure allowed MAC addresses per port, limiting access to specific devices. This directly meets the requirement.
- C
DHCP snooping
Why wrong: DHCP snooping is used to filter DHCP messages and protect against rogue DHCP servers, not to restrict which device can connect to a switch port.
- D
BPDU guard
Why wrong: BPDU guard disables ports that receive Spanning Tree Protocol BPDUs, preventing loops, but it does not control which end devices can connect.
Question 157 of 520
N10-009 Network Security Practice Question
This N10-009 practice question tests your understanding of network security. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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 wants to ensure that only a specific laptop can connect to a particular switch port. The laptop's MAC address is known. Which security feature should be configured?
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
✓
Port security
Port security is the correct feature because it allows the administrator to statically configure the allowed MAC address on a specific switch port. Once configured, the switch will only forward traffic from that MAC address, dropping frames from any other source MAC. This directly fulfills the requirement to restrict access to a single known laptop.
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.
- ✗
802.1X
Why it's wrong here
802.1X requires authentication via a RADIUS server, but it does not rely on a static list of MAC addresses. It is not the best choice for simply restricting access by MAC address.
When this WOULD be correct
802.1X would be correct in a scenario where the network administrator needs to authenticate users or devices before granting network access, typically using credentials or certificates, and the goal is to control access at the network edge based on identity rather than a static MAC address. For example: 'A company wants to require all employees to authenticate with their domain credentials before accessing the wired network.'
- ✓
Port security
Why this is correct
Port security allows the administrator to configure allowed MAC addresses per port, limiting access to specific devices. This directly meets the requirement.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
DHCP snooping
Why it's wrong here
DHCP snooping is used to filter DHCP messages and protect against rogue DHCP servers, not to restrict which device can connect to a switch port.
- ✗
BPDU guard
Why it's wrong here
BPDU guard disables ports that receive Spanning Tree Protocol BPDUs, preventing loops, but it does not control which end devices can connect.
When this WOULD be correct
A network administrator wants to prevent unauthorized switches from being connected to access ports, ensuring STP stability. BPDU guard would be configured to disable a port if it receives a BPDU.
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.
✓Port securityCorrect answer▾
Why this is correct
Port security allows the administrator to configure allowed MAC addresses per port, limiting access to specific devices. This directly meets the requirement.
✗802.1XWrong answer — click to see why▾
Why this is wrong here
802.1X is a network access control method that authenticates users or devices via an authentication server (e.g., RADIUS), but it does not restrict a specific switch port to a single known MAC address without additional configuration. The question explicitly asks for a feature that ensures only a specific laptop (by MAC address) can connect to a particular port, which is the function of port security, not 802.1X.
★ When this WOULD be the correct answer
802.1X would be correct in a scenario where the network administrator needs to authenticate users or devices before granting network access, typically using credentials or certificates, and the goal is to control access at the network edge based on identity rather than a static MAC address. For example: 'A company wants to require all employees to authenticate with their domain credentials before accessing the wired network.'
Why candidates choose this
Candidates may confuse 802.1X with MAC-based authentication, as 802.1X can use MAC addresses as a form of identity (MAC authentication bypass), but it is not the simplest or most direct method for restricting a port to a single known MAC address. Port security is the straightforward answer for MAC address filtering on a switch port.
✗BPDU guardWrong answer — click to see why▾
Why this is wrong here
BPDU guard is used to protect against bridge loops by disabling ports that receive BPDUs, not to restrict access based on MAC address.
★ When this WOULD be the correct answer
A network administrator wants to prevent unauthorized switches from being connected to access ports, ensuring STP stability. BPDU guard would be configured to disable a port if it receives a BPDU.
Why candidates choose this
Candidates may confuse BPDU guard with port security because both involve protecting switch ports, but BPDU guard addresses loop prevention, not MAC-based access control.
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 N10-009 exam often tests the distinction between port security (which controls MAC-level access on a single port) and 802.1X (which controls network access via authentication), leading candidates to mistakenly choose 802.1X because they associate it with 'security' and 'laptop access' without understanding the specific requirement of a static MAC binding.
Detailed technical explanation
How to think about this question
Under the hood, port security uses a secure MAC address table on the switch interface. When configured with the 'switchport port-security mac-address <MAC>' command, the switch adds a static entry for that MAC in the CAM table and will not learn any other MAC on that port. If a violation occurs (e.g., a different MAC tries to send frames), the switch can be configured to shut down the port, restrict traffic, or protect by dropping frames, depending on the violation mode. In a real-world scenario, this is often used in conjunction with sticky MAC learning to dynamically record the first MAC seen and then lock the port.
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 practitioner preparing for the N10-009 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
Quick reference
Access Control Model Comparison
| Model | Acronym | Who Controls Access? | Best For |
|---|---|---|---|
| Discretionary Access Control | DAC | Resource owner | Small teams, file shares |
| Mandatory Access Control | MAC | System / security labels | Classified govt / military |
| Role-Based Access Control | RBAC | Administrator (via roles) | Enterprise environments |
| Attribute-Based Access Control | ABAC | Policy engine (user + resource attributes) | Fine-grained, dynamic policies |
| Rule-Based Access Control | RuBAC | System rules / ACLs | Firewall rules, network ACLs |
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: Port security — Port security is the correct feature because it allows the administrator to statically configure the allowed MAC address on a specific switch port. Once configured, the switch will only forward traffic from that MAC address, dropping frames from any other source MAC. This directly fulfills the requirement to restrict access to a single known laptop.
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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