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📝 Authentication in Linux System

📖 From Operating System • 18. The Linux System • 10 questions available

Practice MCQs for Authentication in Linux System. Test your knowledge with carefully crafted questions across easy, medium, and hard difficulty levels.

🔄 Last updated: 2026-07-27

2
Easy Questions
5
Medium Questions
3
Hard Questions

📝 Sample Questions

Q1. A system administrator wants to allow SSH connections (port 22) only from the trusted IP 192.168.1.10. Which firewall chain ordering will correctly enforce this rule without exposing the SSH service to other hosts?

🔹 A. Place the allow rule in the INPUT chain after a generic deny‑all rule.
🔹 B. Place the allow rule in the INPUT chain before the generic deny‑all rule.
🔹 C. Place the allow rule in the FORWARD chain before any other rules.
🔹 D. Place the allow rule in the OUTPUT chain.

💡 Difficulty: easy | ✅ Correct: B

Q2. If a route‑caching entry for destination 10.0.0.5 expires after a period with no hits, what is the most likely effect on an authentication server that relies on that route for client connections?

🔹 A. Clients will receive faster responses because the cache is cleared.
🔹 B. The server will drop all incoming packets from that destination.
🔹 C. Authentication will be bypassed due to missing route information.
🔹 D. Increased latency as each new packet requires a full FIB lookup before reaching the server.

💡 Difficulty: medium | ✅ Correct: A

Q3. An administrator notices that overlapping rules in the INPUT and FORWARD chains allow unauthenticated traffic to reach a protected service. Which configuration change most effectively closes the bypass?

🔹 A. Add a deny‑all rule to the OUTPUT chain.
🔹 B. Reorder the existing rules in the INPUT chain only.
🔹 C. Place a deny‑all rule at the top of both INPUT and FORWARD chains.
🔹 D. Disable the FORWARD chain entirely.

💡 Difficulty: hard | ✅ Correct: A

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🔗 Related Topics

📝 Linux History📝 The Linux kernel📝 The Linux system📝 Linux distributions📝 Linux licensing
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