A security analyst discovers that an attacker is sending large numbers of incomplete TCP connection requests to a server, causing the server to run out of resources and stop responding to legitimate requests. Which type of attack is this, and which mitigation should be implemented?
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.
Best answer
SYN flood; enable TCP intercept or SYN cookies
The attack is a SYN flood. TCP intercept (or SYN cookies) allows the server to manage half-open connections and mitigate resource exhaustion.
Distractor review
Ping flood; implement rate limiting
Ping floods use ICMP echo requests, not incomplete TCP connections.
Distractor review
Smurf attack; disable IP-directed broadcasts
A Smurf attack sends ICMP echo requests to broadcast addresses with spoofed source IPs, causing amplification, not incomplete TCP handshakes.
Distractor review
ARP poisoning; enable dynamic ARP inspection
ARP poisoning involves sending forged ARP replies to associate IPs with attacker MACs, not exhausting TCP resources.
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 network engineer needs to connect two switches located 400 meters apart. The cable run includes high electromagnetic interference from nearby machinery. The engineer decides to use fiber optic cabling. Which transceiver type and fiber combination should be used to ensure the link reaches 400 meters while remaining cost-effective?
Question 2
A network engineer is designing a new switched network and needs to ensure that broadcast traffic from one department does not reach another department's workstations. The engineer plans to use VLANs. Which of the following must be configured on the switches to isolate broadcast domains as intended?
Question 3
A security engineer is configuring a site-to-site VPN between two branch offices. The requirement is to encrypt all traffic between the two networks using IPsec. Which IPsec mode should be used to encrypt the entire IP packet including the original header?
Question 4
A network administrator is connecting two switches to increase bandwidth and provide redundancy. Which technology should be used to combine multiple physical links into a single logical link?
Question 5
A network administrator is experiencing issues where unauthorized devices are offering IP addresses to clients, causing connectivity problems. Which security feature should be enabled on switches to prevent this?
Question 6
A network administrator is troubleshooting a connectivity issue and suspects the problem is related to the physical cabling. At which layer of the OSI model should the administrator begin their investigation?
FAQ
Questions learners often ask
What does this N10-009 question test?
CIDR notation defines the prefix length.
What is the correct answer to this question?
The correct answer is: SYN flood; enable TCP intercept or SYN cookies — A SYN flood attack exploits the TCP three-way handshake by sending many SYN packets without completing the handshake, exhausting server resources. Mitigations include TCP intercept (e.g., on Cisco devices) or SYN cookies. Ping floods, Smurf attacks, and ARP poisoning have different characteristics.
What should I do if I get this N10-009 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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