Network Engineer interview questions (2026)

Network engineer interviews test networking fundamentals, troubleshooting, security, and design. Then practice them in a free AI mock interview tailored to your exact role.

Fundamentals

• Walk me through what happens when you type a URL and press enter.
• Explain the difference between TCP and UDP.
• What is subnetting, and why does it matter?

Troubleshooting

• A user says 'the internet is slow' — how do you diagnose it?
• How would you troubleshoot intermittent packet loss?
• Walk me through resolving a DNS failure.

Security & design

• How would you design a network for a new office?
• How do you secure a network against common attacks?
• How do you plan for redundancy and failover?