Quick Answer
The answer is DHCP Snooping, Dynamic ARP Inspection (DAI), and IP Source Guard. These three mechanisms work together to prevent ARP spoofing attacks by ensuring that only legitimate IP-to-MAC address mappings are trusted on the network. DHCP Snooping builds a binding table of valid DHCP leases, which DAI then uses to validate ARP packets, dropping any that claim a mismatched IP-MAC pair. IP Source Guard further locks down each switch port by filtering traffic based on that same binding table, discarding packets whose source IP does not match the recorded lease. On the ISC2 Certified in Cybersecurity CC exam, this question tests your understanding of how these features chain together to enforce Layer 2 security; a common trap is choosing only one or two of them, but the exam expects all three as a complete defense. A useful memory tip is to think of the trio as “Snoop, Inspect, Guard” — DHCP Snooping builds the map, DAI inspects ARP messages, and IP Source Guard guards every packet at the port.
This CC 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.
Which THREE security mechanisms should be implemented to secure a network against ARP spoofing attacks? (Choose three.)
IP Source Guard
Prevents IP spoofing by filtering traffic based on DHCP snooping bindings.
Port security
Why wrong: Port security limits MAC addresses but does not prevent ARP spoofing.
Dynamic ARP Inspection (DAI)
Validates ARP packets against DHCP snooping bindings.
MAC address filtering
Why wrong: MAC filtering is static and easily bypassed.
DHCP Snooping
Creates a binding table used by DAI and IP Source Guard.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
IP Source Guard
IP Source Guard (A) is correct because it uses DHCP snooping binding table entries to filter traffic on a per-port basis, dropping packets where the source IP address does not match the binding. This prevents an attacker from spoofing a legitimate host's IP address in ARP spoofing attacks by ensuring only valid IP-to-MAC mappings are allowed on the port.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
IP Source Guard
Why this is correct
Prevents IP spoofing by filtering traffic based on DHCP snooping bindings.
Related concept
Read the scenario before looking for a memorised answer.
Port security
Why it's wrong here
Port security limits MAC addresses but does not prevent ARP spoofing.
Dynamic ARP Inspection (DAI)
Why this is correct
Validates ARP packets against DHCP snooping bindings.
Related concept
Read the scenario before looking for a memorised answer.
MAC address filtering
Why it's wrong here
MAC filtering is static and easily bypassed.
DHCP Snooping
Why this is correct
Creates a binding table used by DAI and IP Source Guard.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
ISC2 often tests the misconception that port security or MAC filtering can prevent ARP spoofing, but these only control MAC addresses, not the IP-to-MAC bindings that ARP spoofing exploits.
Detailed technical explanation
ARP spoofing exploits the lack of authentication in the ARP protocol (RFC 826) by sending gratuitous ARP replies to poison the target's ARP cache. DAI (C) intercepts all ARP packets on untrusted ports and validates them against the DHCP snooping binding table, dropping invalid ones. DHCP snooping (E) builds the binding table by monitoring DHCP messages and creates a trusted/untrusted port hierarchy, which is essential for both DAI and IP Source Guard to function correctly.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A security analyst at a medium-sized enterprise encounters this scenario during an investigation or architecture review. The correct answer reflects best practice for the specific threat or control described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Security exam questions test whether you can match controls to threats in context — not just recall definitions.
What to study next
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FAQ
Network Security — This question tests Network Security — Read the scenario before looking for a memorised answer..
The correct answer is: IP Source Guard — IP Source Guard (A) is correct because it uses DHCP snooping binding table entries to filter traffic on a per-port basis, dropping packets where the source IP address does not match the binding. This prevents an attacker from spoofing a legitimate host's IP address in ARP spoofing attacks by ensuring only valid IP-to-MAC mappings are allowed on the port.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 30, 2026
This CC practice question is part of Courseiva's free ISC2 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 CC exam.
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