Question 1mediummultiple choice
Full question →mediummultiple choiceObjective-mapped
Several users on the same subnet report intermittent inability to reach the default gateway. A packet capture shows ARP replies mapping the gateway IP to a different MAC address, and the same host keeps sending those replies every few seconds. What attack is most likely?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Distractor review
Replay attack
A replay attack reuses captured valid traffic later, but the key clue here is false ARP information on the local network.
B
Best answer
ARP spoofing
ARP spoofing, also called ARP poisoning, forges ARP replies so hosts associate the gateway IP with the attacker MAC address.
C
Distractor review
DNS amplification
DNS amplification relies on reflected DNS traffic and large response volumes, not altered ARP mappings on a local subnet.
D
Distractor review
Man-in-the-middle via TLS downgrade
A man-in-the-middle can happen in many ways, but the capture specifically shows forged ARP replies rather than a TLS issue.
Common exam trap
Common exam trap: usable hosts are not the same as total addresses
Subnetting questions often tempt you into counting all addresses. In normal IPv4 subnets, the network and broadcast addresses are not usable host addresses.
Technical deep dive
How to think about this question
Subnetting questions test whether you can identify the network, broadcast address, usable range, mask and correct subnet. Slow down enough to calculate the block size correctly.
KKey Concepts to Remember
- CIDR notation defines the prefix length.
- Block size helps identify subnet boundaries.
- Network and broadcast addresses are not usable hosts in normal IPv4 subnets.
- The required host count determines the smallest suitable subnet.
TExam Day Tips
- Write the block size before choosing the subnet.
- Check whether the question asks for hosts, subnets or a specific address range.
- Do not confuse /24, /25, /26 and /27 host counts.
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More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
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Question 2
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Question 3
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Question 4
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Question 5
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Question 6
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FAQ
Questions learners often ask
What does this SY0-701 question test?
CIDR notation defines the prefix length.
What is the correct answer to this question?
The correct answer is: ARP spoofing — The most likely attack is ARP spoofing because the attacker is repeatedly sending forged ARP replies that bind the gateway IP address to a different MAC address. That causes hosts on the local subnet to send traffic to the attacker instead of the real gateway, which can interrupt access or enable interception. The repeating replies help maintain the poisoned cache as it ages out and gets refreshed. Why others are wrong: A replay attack would reuse previously captured packets, but it would not change MAC-to-IP mappings in ARP tables. DNS amplification involves abusing external servers to overwhelm a target with large DNS responses, which does not fit the local subnet symptoms. A generic man-in-the-middle explanation is too broad; the specific mechanism shown in the capture is ARP poisoning.
What should I do if I get this SY0-701 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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