Question 1easymultiple choice
Full question →easymultiple choiceObjective-mapped
Several users on the same subnet report that their traffic to the default gateway is intermittently slow and sometimes reaches the wrong device. A packet capture shows ARP replies that map the gateway IP to a different MAC address. What attack is most likely occurring?
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
Best answer
ARP spoofing, which poisons address resolution on the local network
ARP spoofing sends false ARP information so hosts associate the gateway IP with the attacker's MAC address.
B
Distractor review
DNS amplification, which overwhelms the target with reflected DNS traffic
DNS amplification is a denial-of-service technique and does not involve changing ARP mappings on a subnet.
C
Distractor review
Replay attack, which resends captured authentication data
Replay attacks reuse captured traffic, but they do not typically alter gateway MAC mappings.
D
Distractor review
Port scanning, which probes hosts for open services and ports
Port scanning is reconnaissance and would not explain incorrect ARP replies or gateway hijacking.
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.
Question 1
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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, which poisons address resolution on the local network — The best answer is ARP spoofing. On a local network, ARP maps IP addresses to MAC addresses. If an attacker sends forged ARP replies that bind the gateway IP to the attacker’s MAC address, nearby systems can send traffic to the wrong device. This can enable interception, redirection, or service disruption. The clue about the wrong MAC address in packet capture is the strongest indicator. Why others are wrong: DNS amplification is a denial-of-service method that uses reflected DNS responses, not local ARP table poisoning. Replay attacks involve reusing captured authentication or session data. Port scanning is discovery activity and would not cause the gateway IP to point to a different MAC address.
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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