Question 1mediummultiple choice
Full question →mediummultiple choiceObjective-mapped
A public web server becomes unreachable during an outage. Netflow shows a large number of DNS responses arriving from many open resolvers, while the server itself only sent tiny spoofed DNS queries with the victim's address as the source. What type of attack is this?
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
DNS zone transfer abuse against the organization.
Zone transfer abuse would involve pulling DNS records from an authoritative server, not flooding a victim with amplified responses.
B
Best answer
DNS amplification reflection denial-of-service.
This is DNS amplification reflection because the attacker spoofs the victim's IP address in small requests to open resolvers, causing large responses to be sent to the victim instead. The result is a bandwidth flood that can make the server unreachable even though the victim never initiated the traffic. The key clues are tiny queries, spoofed source addresses, many resolvers, and a high volume of unsolicited responses. This is a classic distributed denial-of-service pattern.
C
Distractor review
A replay attack against a web application session token.
Replay attacks reuse captured credentials or tokens, but they do not produce the resolver-based traffic pattern described in the scenario.
D
Distractor review
ARP poisoning inside the local network segment.
ARP poisoning is a local Layer 2 attack and would not explain internet-scale DNS responses from external resolvers.
Common exam trap
Common exam trap: OSPF can fail even when IP connectivity looks correct
OSPF neighbour formation depends on matching areas, timers, network type, authentication and passive-interface behaviour. Do not choose an answer only because the devices can ping.
Technical deep dive
How to think about this question
OSPF questions usually test the details that control adjacency and route selection. Read the neighbour state, area, router ID and interface configuration before deciding what is wrong.
KKey Concepts to Remember
- OSPF neighbours must agree on key parameters.
- Router ID selection can affect neighbour relationships and LSDB output.
- OSPF cost influences the preferred path.
- A route can appear in OSPF information but not become the installed route.
TExam Day Tips
- Check area mismatch first when OSPF adjacency fails.
- Review passive interfaces when a network is advertised but no neighbour forms.
- Use show ip ospf neighbor and show ip route clues carefully.
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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?
OSPF neighbours must agree on key parameters.
What is the correct answer to this question?
The correct answer is: DNS amplification reflection denial-of-service. — The best answer is DNS amplification reflection denial-of-service. The attacker spoofs the victim's address in very small DNS queries, and the open resolvers send much larger replies to the victim, overwhelming bandwidth or packet-processing capacity. That is why the server becomes unreachable even though it never made the requests. The pattern of many resolvers and large responses is a strong indicator of reflection-based DDoS. Understanding the traffic direction and spoofing behavior is key to identifying the attack. Why others are wrong: A zone transfer is a legitimate DNS replication process or a misconfiguration issue; it does not create a response flood from many resolvers. Replay attacks involve reusing authentication data, not abusing public DNS resolvers for traffic amplification. ARP poisoning occurs on a local broadcast domain and would not explain wide-area DNS traffic. The distinguishing feature here is the use of third-party resolvers to multiply traffic against the victim.
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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