Top 20 CCNA Interview Questions and Answers (2025)

The Cisco Certified Network Associate (CCNA) certification remains one of the most sought-after credentials in the IT industry. As networks grow more complex in 2025, employers seek professionals with foundational networking knowledge and hands-on experience in troubleshooting, configuration, and security. Below is a categorized list of 20 updated interview questions and answers designed to prepare you for your next CCNA role.

Behavioral Questions

• 1. Tell me about a time you resolved a critical network issue.
  I identified a misconfigured static route during a network outage, corrected it quickly, and documented the fix for future reference.
• 2. How do you stay current with new networking technologies?
  I follow Cisco blogs, complete labs on Packet Tracer, and subscribe to industry newsletters like Network World and TechTarget.
• 3. Describe a situation where you worked with a team to solve a technical problem.
  I collaborated with a security engineer to isolate a VLAN misrouting issue that was impacting internal application access.
• 4. Have you ever disagreed with a senior colleague on a network design?
  Yes, I respectfully shared an alternative topology backed by documentation, which was later adopted after a peer review.
• 5. How do you handle stress when troubleshooting under pressure?
  I stay calm, break down the problem into layers (physical, data link, etc.), and document each test to avoid repeating steps.

Situational Questions

• 6. What would you do if you noticed intermittent packet loss?
  I’d use ping and traceroute to identify the point of failure, then examine interface statistics and error logs on the suspected device.
• 7. If your switch suddenly reboots, how would you proceed?
  I’d check for power issues, inspect syslog messages, verify the IOS version, and investigate recent configuration changes.
• 8. A router is not propagating routes. What’s your plan?
  I’d verify routing protocol configuration, neighbor relationships, and ensure ACLs aren’t blocking routing updates.
• 9. How would you secure a remote branch connection?
  I’d implement site-to-site IPsec VPN with proper encryption and use access lists to restrict sensitive traffic.
• 10. A new device isn’t connecting to the network. What steps do you take?
  I’d check cabling, verify VLAN membership, inspect DHCP assignment, and ping the gateway to isolate the problem.

Technical Questions

• 11. What are the differences between TCP and UDP?
  TCP is connection-oriented with guaranteed delivery, while UDP is connectionless, faster, and used for real-time applications.
• 12. Explain how STP (Spanning Tree Protocol) works.
  STP prevents loops in a Layer 2 network by blocking redundant paths and electing a root bridge through BPDU exchanges.
• 13. How do routers and switches differ in functionality?
  Routers operate at Layer 3 to connect different networks, while switches work at Layer 2 to forward traffic within the same network.
• 14. What is the purpose of subnetting?
  Subnetting divides larger networks into smaller, manageable sections to improve efficiency and security.
• 15. How does NAT work and when is it used?
  NAT translates private IPs to a public IP for internet access, commonly used in home and corporate networks for security and IP conservation.

Cultural Fit Questions

• 16. Why did you pursue CCNA certification?
  I’ve always enjoyed networking fundamentals, and CCNA provided a structured path to build expertise and credibility.
• 17. What type of work environment helps you perform best?
  I thrive in collaborative teams where knowledge-sharing is encouraged and problem-solving is valued over blame.
• 18. How do you ensure your documentation is effective?
  I maintain clear diagrams, version-controlled configs, and step-by-step troubleshooting logs for team reference.
• 19. What do you value most in a network team?
  I value transparency, peer learning, and consistent communication, which ensure smoother network operations.
• 20. How do you respond to feedback on your technical work?
  I welcome constructive feedback and use it as a learning opportunity to refine my approach and improve performance.