Question 1mediummultiple choice
Full question →mediummultiple choiceObjective-mapped
Exhibit
Network capture summary: Host 10.20.14.25 sends ARP requests for 10.20.14.1 Multiple ARP replies received: 10.20.14.1 is-at 02:42:ac:11:00:05 10.20.14.1 is-at 02:42:ac:11:00:05 10.20.14.1 is-at 66:77:88:99:aa:bb Client gateway cache alternates between the legitimate gateway MAC and 66:77:88:99:aa:bb every few seconds. Users report brief certificate warnings when opening internal sites.
Based on the exhibit, what network attack is most likely occurring on the office LAN?
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 poisoning, because a rogue system is sending false layer 2 address mappings.
ARP poisoning is the best answer because the capture shows false ARP replies mapping the gateway IP to a different MAC address. The alternating gateway cache entries and certificate warnings are consistent with traffic being redirected through an attacker in a man-in-the-middle position.
B
Distractor review
Replay attack, because the same ARP reply appears multiple times.
A replay attack typically reuses captured authentication or transaction data. The repeated ARP replies here are not evidence of replayed credentials; they indicate address spoofing on the local network.
C
Distractor review
Denial of service, because users notice certificate warnings.
A DoS attack aims to overwhelm resources and make services unavailable. The exhibit shows traffic redirection and address manipulation, not a flood or outage condition.
D
Distractor review
DNS poisoning, because the users cannot reach internal sites cleanly.
DNS poisoning affects name resolution records, not the ARP cache. The evidence is at layer 2, where an IP address is mapped to the wrong MAC address on the LAN.
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
A laptop is suspected of being used in a malware incident. It is still powered on and connected to Wi-Fi. What should the responder do before shutting it down?
Question 2
An employee reports a ransomware note on a file server. The server is still powered on, shares are still being accessed, and management wants service restored as quickly as possible. What should the incident response team do first?
Question 3
An employee reports a ransomware note on a finance laptop. The laptop is still powered on, connected to Wi-Fi, and the user says they were just working in a spreadsheet. Management wants the fastest safe response that also preserves evidence. What should the responder do first?
Question 4
You are handed a company laptop suspected in an insider theft case. Legal says the evidence may be needed in court. Which action best preserves admissibility?
Question 5
A developer wants to reduce the risk of SQL injection in a new customer search form. Which two changes are the best mitigations? Select two.
Question 6
A branch office uses a flat LAN, and a compromise on one user workstation could spread quickly to finance systems. Management wants finance workstations isolated from general users, but finance staff still need access to a central finance application and network printer. What is the best design change?
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 poisoning, because a rogue system is sending false layer 2 address mappings. — The correct answer is ARP poisoning. The host is receiving forged ARP replies that cause the gateway IP to resolve to a rogue MAC address. That can redirect traffic through an attacker, which explains the brief certificate warnings and the changing cache entries. In a switched LAN, this is a common technique for local man-in-the-middle interception. Why others are wrong: Replay attacks reuse captured traffic, usually for authentication or transactions, but this log shows address spoofing instead. DoS attacks focus on availability through flooding or resource exhaustion, which is not the behavior described. DNS poisoning happens at name resolution, while the exhibit clearly shows ARP cache manipulation on the local subnet. The clues point to ARP poisoning specifically.
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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