Mock interview practice

Network Engineer interview questions & mock practice

Practise Network Engineer questions freeCreate my free profile

What interview questions are asked for a Network Engineer?

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 out loud with the free timed practice below before the real one.

  • TCP/IP
  • Routing & Switching
  • Subnetting
  • DNS
  • VLAN
  • Firewalls
  • Troubleshooting

Free interview practice · Network Engineer

Practise your Network Engineer interview now — free

Step through the 12 most-asked Network Engineer questions one at a time, under a timer, just like the real thing. Jot your answer, then reveal what a strong answer covers. No signup needed to practise.

Interview rounds

The Network Engineer interview process

Routing, switching, TCP/IP and troubleshooting — the network-engineering interview for IT infrastructure, telecom and enterprise networking teams.

1. Networking fundamentals

OSI model, TCP/IP, subnetting and protocols.

2. Routing & switching

Routers, switches, VLANs, OSPF/BGP and NAT.

3. Troubleshooting round

Diagnose connectivity and performance issues.

4. Security & scenario

Firewalls, VPNs and a real network design problem.

Most-asked questions

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 the timed practice above.

  1. 1. Explain the OSI model and what happens at each layer.
  2. 2. What is the difference between TCP and UDP, and when do you use each?
  3. 3. Explain the difference between a router, a switch and a hub.
  4. 4. What is subnetting, and how do you calculate the number of hosts in a subnet?
  5. 5. What is the difference between a public and a private IP address, and what is NAT?
  6. 6. Explain how DNS resolution works step by step.
  7. 7. What is the difference between a VLAN and a subnet?
  8. 8. Explain the difference between OSPF and BGP routing protocols.
  9. 9. What happens when you type a URL and press enter, at the network level?
  10. 10. What is the difference between a default gateway and a DNS server?
  11. 11. How would you troubleshoot a user who can't reach a website?
  12. 12. What is the three-way handshake in TCP?
How to prepare

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

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. Practise them with the free timed practice on this page.

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 rehearse every question out loud with the timed practice on this page 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 the Network Engineer mock interview practice free?

Yes. The questions, the answer guidance and the timed practice on this page are free and need no signup. With a free OnJob account you can also take timed role tests and free certification tests. Personalised AI role and skill tests are part of the paid plans.

Free practice, no signup to start

Ace your Network Engineer interview

Rehearse every Network Engineer question out loud on this page, then sign in to take a timed role test or a free certification in the OnJob practice hub.

Open the practice hubSee certifications
Explore the full cluster

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.