20+ practice questions focused on Network Security — one of the most tested topics on the ISC2 Certified in Cybersecurity CC exam. Each question includes a detailed explanation so you learn why the right answer is correct.
Start Network Security PracticeA security analyst notices that an internal web server is receiving a high volume of TCP SYN packets from a single external IP address, but the server is not sending SYN-ACK replies. The server's CPU and memory usage are normal. What is the most likely cause?
Explanation: The correct answer is B because a SYN flood attack works by sending a high volume of TCP SYN packets to a server, filling its half-open connection queue (the backlog) and preventing it from completing the three-way handshake. Since the server's CPU and memory are normal, the issue is not resource exhaustion but rather the queue being saturated, causing the server to stop sending SYN-ACK replies to new connection requests.
A network administrator is designing a DMZ to host a public-facing web server and a database server that should only be accessible from the web server. Which of the following firewall rule sets best achieves this design?
Explanation: Option A is correct because it implements the principle of least privilege for a DMZ: it allows inbound HTTP/HTTPS traffic (ports 80/443) to the public-facing web server, then permits only the web server to initiate outbound connections to the database server on port 3306 (MySQL/MariaDB default), and denies all other traffic. This ensures the database is not directly accessible from the internet, reducing the attack surface while still supporting the required application flow.
A company's network uses 802.1X authentication with PEAP-MSCHAPv2 on wired ports. Users report that after a recent switch firmware update, some workstations fail to authenticate intermittently, while others work fine. The authentication server logs show 'Authentication failed: Unknown CA certificate' for affected workstations. What is the most likely cause?
Explanation: The error 'Unknown CA certificate' indicates that the client does not trust the certificate presented by the RADIUS server during PEAP-MSCHAPv2 authentication. After a switch firmware update, the switch may have been reconfigured to use a different server certificate (e.g., a self-signed or internally issued certificate) that is not in the trusted root store of the affected workstations. Since PEAP requires the client to validate the server certificate, a mismatch causes intermittent authentication failures.
A security engineer is configuring a network intrusion detection system (NIDS) to monitor traffic on a critical subnet. To minimize false positives, which of the following should the engineer baseline first?
Explanation: Baselining normal traffic patterns during peak business hours establishes a reference of legitimate network behavior, which is essential for a NIDS to distinguish benign anomalies from actual threats. Without this baseline, the NIDS may generate false positives by flagging legitimate peak-hour traffic spikes as malicious. This aligns with the principle that anomaly-based detection relies on a statistical model of normal activity to reduce noise.
A company's remote access VPN uses IPsec with pre-shared keys. Employees report that they cannot connect from home. The VPN server logs show 'IKE authentication failed.' The help desk confirms the pre-shared keys are correct. Which of the following is the most likely cause?
Explanation: Option D is correct because 'IKE authentication failed' specifically indicates a failure during IKE phase 1, where the peers negotiate security parameters. Even if the pre-shared key is correct, mismatched encryption (e.g., AES vs. 3DES), hash (e.g., SHA-1 vs. SHA-256), or Diffie-Hellman group (e.g., group 2 vs. group 14) will cause the IKE SA to fail, preventing phase 1 authentication from completing.
+15 more Network Security questions available
Practice all Network Security questions1. Baseline your knowledge
Start with 10 questions to gauge your current understanding of Network Security. This tells you whether you need a concept refresher or just practice.
2. Review every explanation
For each question — right or wrong — read the full explanation. Understanding why an answer is correct is more valuable than knowing the answer itself.
3. Focus on exam traps
Network Security questions on the CC frequently use trap wording. Look for subtle differences in answers that test your precision, not just general knowledge.
4. Reach 80% consistently
Do repeated sessions until you score 80%+ three times in a row. Then move to mixed-mode practice to test cross-topic recall under realistic conditions.
The exact number varies per candidate. Network Security is tested as part of the ISC2 Certified in Cybersecurity CC blueprint. Practicing with targeted Network Security questions ensures you can handle any format or difficulty that appears.
Yes. Courseiva provides free CC practice questions across all exam topics and domains. The platform includes topic-based practice, mock exams, missed-question review, bookmarked questions, and readiness tracking — no account required.
Difficulty is subjective, but Network Security is a high-priority exam concept tested in multiple ways — direct recall, scenario analysis, and command-output interpretation. Consistent practice is the best way to build confidence.
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