- A
DHCP Snooping
DHCP Snooping filters DHCP messages and only allows DHCP offers from trusted ports, blocking rogue DHCP servers.
- B
Dynamic ARP Inspection
Why wrong: DAI validates ARP packets to prevent ARP spoofing, not DHCP-related attacks.
- C
IP Source Guard
Why wrong: IP Source Guard prevents IP spoofing by verifying source IP addresses against DHCP snooping bindings, but does not block rogue DHCP servers.
- D
Port Security
Why wrong: Port Security restricts the number of MAC addresses per port, but does not prevent unauthorized DHCP servers.
Question 142 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 notices that several workstations on the network are receiving IP addresses from an unknown source, causing intermittent connectivity issues. The DHCP server is located in the server room and is the only authorized DHCP server. Which security feature should be implemented on the access switches to prevent rogue DHCP servers from distributing IP addresses?
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
✓
DHCP Snooping
DHCP Snooping is the correct security feature because it filters untrusted DHCP messages on access switches. By configuring ports connected to end-user workstations as untrusted, the switch drops DHCP server responses (OFFER, ACK) received on those ports, preventing rogue DHCP servers from distributing IP addresses. This ensures only the authorized DHCP server in the server room can provide IP configurations.
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.
- ✓
DHCP Snooping
Why this is correct
DHCP Snooping filters DHCP messages and only allows DHCP offers from trusted ports, blocking rogue DHCP servers.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Dynamic ARP Inspection
When this WOULD be correct
A network administrator notices intermittent connectivity and ARP cache poisoning attacks on the LAN. Which security feature should be implemented on switches to validate ARP packets and prevent man-in-the-middle attacks?
- ✗
IP Source Guard
Why it's wrong here
IP Source Guard prevents IP spoofing by verifying source IP addresses against DHCP snooping bindings, but does not block rogue DHCP servers.
When this WOULD be correct
A network administrator wants to prevent devices from spoofing IP addresses on the network. IP Source Guard would be the correct answer when the question asks for a security feature that filters IP traffic on a per-port basis using the DHCP snooping binding table to block unauthorized IP source addresses.
- ✗
Port Security
Why it's wrong here
Port Security restricts the number of MAC addresses per port, but does not prevent unauthorized DHCP servers.
When this WOULD be correct
Port Security would be correct in a scenario where the question asks how to prevent unauthorized devices from connecting to the network by limiting the number of MAC addresses allowed on a switch port, such as in a high-security environment to prevent rogue laptops or switches from plugging in.
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.
✓DHCP SnoopingCorrect answer▾
Why this is correct
DHCP Snooping filters DHCP messages and only allows DHCP offers from trusted ports, blocking rogue DHCP servers.
✗Dynamic ARP InspectionWrong answer — click to see why▾
Why this is wrong here
Dynamic ARP Inspection (DAI) validates ARP packets to prevent ARP spoofing, not DHCP server unauthorized distribution. The question specifically asks about rogue DHCP servers, which DHCP Snooping addresses by filtering DHCP messages on untrusted ports.
★ When this WOULD be the correct answer
A network administrator notices intermittent connectivity and ARP cache poisoning attacks on the LAN. Which security feature should be implemented on switches to validate ARP packets and prevent man-in-the-middle attacks?
Why candidates choose this
Candidates may confuse DAI with DHCP Snooping because both are security features that rely on DHCP Snooping binding tables and are often implemented together, leading to the mistaken belief that DAI directly prevents rogue DHCP servers.
✗IP Source GuardWrong answer — click to see why▾
Why this is wrong here
IP Source Guard is used to prevent IP spoofing by filtering traffic based on the DHCP snooping binding table, but it does not directly prevent rogue DHCP servers from distributing IP addresses. The question specifically asks for a feature to block unauthorized DHCP servers, which is DHCP Snooping.
★ When this WOULD be the correct answer
A network administrator wants to prevent devices from spoofing IP addresses on the network. IP Source Guard would be the correct answer when the question asks for a security feature that filters IP traffic on a per-port basis using the DHCP snooping binding table to block unauthorized IP source addresses.
Why candidates choose this
Candidates may confuse IP Source Guard with DHCP Snooping because both rely on the DHCP snooping binding table and are often implemented together, leading to the mistaken belief that IP Source Guard also prevents rogue DHCP servers.
✗Port SecurityWrong answer — click to see why▾
Why this is wrong here
Port Security limits the number of MAC addresses per port but does not inspect DHCP messages or block rogue DHCP servers. It cannot prevent unauthorized DHCP offers from being forwarded.
★ When this WOULD be the correct answer
Port Security would be correct in a scenario where the question asks how to prevent unauthorized devices from connecting to the network by limiting the number of MAC addresses allowed on a switch port, such as in a high-security environment to prevent rogue laptops or switches from plugging in.
Why candidates choose this
Candidates may think Port Security can block rogue servers because it controls device access, but it operates at Layer 2 and does not filter DHCP traffic specifically.
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 DHCP Snooping and Dynamic ARP Inspection, where candidates mistakenly choose DAI because they confuse DHCP spoofing with ARP spoofing, but DHCP Snooping is the specific mechanism to block rogue DHCP servers.
Detailed technical explanation
How to think about this question
DHCP Snooping operates by building a DHCP snooping binding table that maps client MAC addresses, IP addresses, VLAN, and port information. When a switch port is set to untrusted, the switch drops any DHCPOFFER, DHCPACK, or DHCPNAK messages received on that port, as these should only originate from the trusted uplink port connected to the authorized DHCP server. In a real-world scenario, a malicious user plugging a consumer router into an access port would be blocked from handing out IP addresses because the switch silently drops the DHCP server responses.
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.
Visual reference
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: DHCP Snooping — DHCP Snooping is the correct security feature because it filters untrusted DHCP messages on access switches. By configuring ports connected to end-user workstations as untrusted, the switch drops DHCP server responses (OFFER, ACK) received on those ports, preventing rogue DHCP servers from distributing IP addresses. This ensures only the authorized DHCP server in the server room can provide IP configurations.
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.