Network Engineer interview questions & mock practice
A Network Engineer interview in 2026 runs across 4 rounds — networking fundamentals, routing & switching, troubleshooting round, security & scenario. Below are the most-asked Network Engineer interview questions and a focused prep plan. Rehearse every answer with OnJob's free AI mock interview and get instant, specific feedback before the real one.
The Network Engineer interview process
Routing, switching, TCP/IP and troubleshooting — the network-engineering interview for IT infrastructure, telecom and enterprise networking teams.
Networking fundamentals
OSI model, TCP/IP, subnetting and protocols.
Routing & switching
Routers, switches, VLANs, OSPF/BGP and NAT.
Troubleshooting round
Diagnose connectivity and performance issues.
Security & scenario
Firewalls, VPNs and a real network design problem.
Most-asked Network Engineer interview questions
12 of the questions Network Engineer candidates are asked most often in India. Practise answering each one out loud in your AI mock interview.
- 1. Explain the OSI model and what happens at each layer.
- 2. What is the difference between TCP and UDP, and when do you use each?
- 3. Explain the difference between a router, a switch and a hub.
- 4. What is subnetting, and how do you calculate the number of hosts in a subnet?
- 5. What is the difference between a public and a private IP address, and what is NAT?
- 6. Explain how DNS resolution works step by step.
- 7. What is the difference between a VLAN and a subnet?
- 8. Explain the difference between OSPF and BGP routing protocols.
- 9. What happens when you type a URL and press enter, at the network level?
- 10. What is the difference between a default gateway and a DNS server?
- 11. How would you troubleshoot a user who can't reach a website?
- 12. What is the three-way handshake in TCP?
How to prepare for your Network Engineer interview
Know the OSI and TCP/IP models cold — interviewers map almost every question back to a layer.
Master subnetting and be able to do it quickly on paper (CIDR, host counts, network/broadcast addresses).
Understand routing and switching: VLANs, trunking, OSPF/BGP basics, NAT and ACLs.
Practice structured troubleshooting (ping, traceroute, nslookup) — walk the path layer by layer.
If you have it, mention CCNA; otherwise be solid on the concepts it covers.
Practise other roles
- Software Engineer
- Frontend Developer
- Backend Developer
- Full Stack Developer
- Data Analyst
- Data Scientist
- Product Manager
- DevOps Engineer
- Java Developer
- Python Developer
- UI/UX Designer
- Sales / Business Development
- Digital Marketing
- HR / Recruiter
- Accountant
- Customer Support
- Data Engineer
- Machine Learning Engineer
- QA / Test Engineer
- Android Developer
- iOS Developer
- Business Analyst
- Project Manager
- Scrum Master
- SQL Developer
- React Developer
- Node.js Developer
- Cloud Engineer (AWS)
- Cybersecurity Analyst
- Database Administrator
- SEO Specialist
- Content Writer
- Graphic Designer
- Sales Executive
- Business Development Manager
- Operations Manager
- Financial Analyst
- Chartered Accountant
- Customer Success Manager
- Technical Support Engineer
- Civil Engineer
Interview prep guides
Network Engineer interview — FAQs
What questions are asked in a Network Engineer interview?
Common Network Engineer interview questions include: Explain the OSI model and what happens at each layer. What is the difference between TCP and UDP, and when do you use each? Explain the difference between a router, a switch and a hub. What is subnetting, and how do you calculate the number of hosts in a subnet? Interviews usually run across 4 rounds — Networking fundamentals, Routing & switching, Troubleshooting round, Security & scenario. Practice all of them with instant AI feedback using OnJob's free mock interview.
How many rounds are in a Network Engineer interview?
A typical Network Engineer interview has 4 rounds: Networking fundamentals (OSI model, TCP/IP, subnetting and protocols.); Routing & switching (Routers, switches, VLANs, OSPF/BGP and NAT.); Troubleshooting round (Diagnose connectivity and performance issues.); Security & scenario (Firewalls, VPNs and a real network design problem.).
How do I prepare for a Network Engineer interview?
To prepare for a Network Engineer interview: Know the OSI and TCP/IP models cold — interviewers map almost every question back to a layer. Master subnetting and be able to do it quickly on paper (CIDR, host counts, network/broadcast addresses). Understand routing and switching: VLANs, trunking, OSPF/BGP basics, NAT and ACLs. Then run a full AI mock interview on OnJob to rehearse out loud and get instant, specific feedback before the real thing.
What skills do I need for a Network Engineer role?
Core Network Engineer skills tested in interviews include TCP/IP, Routing & Switching, Subnetting, DNS, VLAN, Firewalls, Troubleshooting. OnJob shows you exactly which of these skills stand between you and a 100% match on every live Network Engineer job.
Is OnJob's Network Engineer mock interview free?
Yes. OnJob's AI mock interview is free to start (₹0) and gives you instant feedback on your answers. Pro (₹99/month) adds unlimited interview-prep AI alongside recruiter tracking and unlimited applications.
Ace your Network Engineer interview
Rehearse every Network Engineer question out loud with OnJob's AI mock interview and get instant, specific feedback. Then apply to AI-matched jobs in one click — free to start.
Everything about Network Engineer on OnJob
Move across the whole Network Engineer topic — live openings, real salary data, the job description, interview prep, and early-career routes — all in one place.