The answer is to apply an access control list (ACL) on the switch port to block outbound ICMP and non-essential TCP traffic from the server. This is correct because the ACL immediately stops the anomalous traffic—the ICMP Echo requests and the resulting TCP SYN flood—without taking the critical database server offline, thereby containing the compromised server without downtime. On the Systems Security Certified Practitioner SSCP exam, this scenario tests your understanding of network segmentation and access control as a first-response containment strategy, often appearing in questions about incident response and network security controls. A common trap is to immediately isolate the server by disabling the port, which causes downtime; the better approach is a granular ACL that preserves legitimate database operations. Memory tip: think “ACL before unplug” — always filter first, then investigate.
SSCP Network and Communications Security Practice Question
This SSCP practice question tests your understanding of network and communications security. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A large data center uses a three-tier architecture with core, aggregation, and access switches. The security team detects anomalous traffic patterns: every night at 2:00 AM, a single server (IP 10.10.10.50) sends large ICMP Echo requests to multiple external IPs, followed by a flood of TCP SYN packets from those external IPs back to the server. The server is a critical database server that should not initiate outbound connections. The team suspects the server is compromised. The network team wants to contain the threat without taking the server offline immediately. Which action should they take first?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "first"
Why it matters: Order matters here. You are being tested on which action comes before the others — not which action is generally useful.
Clue: "immediately / without restart"
Why it matters: Time or reboot constraint — the correct answer must take effect right away without requiring a reboot or reload.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Apply an access control list (ACL) on the switch port to block outbound ICMP and non-essential TCP traffic from the server.
Option A is correct because applying an ACL on the switch port to block outbound ICMP and non-essential TCP traffic from the server immediately stops the anomalous traffic (ICMP Echo requests and TCP SYN flood responses) without taking the critical database server offline. This containment approach preserves server availability for legitimate database operations while preventing further malicious outbound activity, aligning with the goal of containing the threat without immediate downtime.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
Apply an access control list (ACL) on the switch port to block outbound ICMP and non-essential TCP traffic from the server.
Why this is correct
This restricts the server's outbound traffic without fully disconnecting it.
Clue confirmation
The clue words "first", "immediately / without restart" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
Add a firewall rule to block all traffic to and from the server's IP.
Why it's wrong here
This would block all traffic, including legitimate database queries.
✗
Move the server to a quarantine VLAN with no route to the internet.
Why it's wrong here
Moving the server might affect other services and is less immediate than an ACL.
✗
Shut down the switch port to disconnect the server immediately.
Why it's wrong here
This would take the critical database server offline.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often choose a more drastic action like shutting down the port or blocking all traffic, failing to recognize that a granular ACL on the switch port can surgically stop the malicious traffic while keeping the server online for its primary role.
Detailed technical explanation
How to think about this question
ICMP Echo requests (ping) and TCP SYN packets are commonly used in DDoS amplification attacks; the server's outbound ICMP triggers a flood of SYN responses from external IPs, indicating a potential reflection attack or botnet activity. ACLs on switch ports operate at Layer 3/4 and can filter specific protocols (e.g., ICMP type 8 for Echo) and TCP flags (SYN) without affecting legitimate database traffic, such as inbound SQL queries. In real-world scenarios, this approach allows security teams to buy time for forensic analysis while maintaining critical services.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A SOC analyst notices unusual lateral movement in the network at 2 AM. The IR playbook dictates: identify and contain (isolate the affected machine), then eradicate (remove the malware), then recover (restore from backup), then document. Skipping containment before eradication risks the attacker regaining access. Questions like this test the sequence and rationale of incident response phases.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Network and Communications Security — This question tests Network and Communications Security — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Apply an access control list (ACL) on the switch port to block outbound ICMP and non-essential TCP traffic from the server. — Option A is correct because applying an ACL on the switch port to block outbound ICMP and non-essential TCP traffic from the server immediately stops the anomalous traffic (ICMP Echo requests and TCP SYN flood responses) without taking the critical database server offline. This containment approach preserves server availability for legitimate database operations while preventing further malicious outbound activity, aligning with the goal of containing the threat without immediate downtime.
What should I do if I get this SSCP question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "first", "immediately / without restart". Order matters here. You are being tested on which action comes before the others — not which action is generally useful.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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