In this guide
- What does a junior network engineer interview look like?
- Which fundamentals questions come up most?
- Which routing and switching questions should you prepare?
- How do you handle troubleshooting scenarios?
- What behavioural questions do they ask?
- How do you write an entry level network engineer CV?
- What should you ask at the end?
- How Experiencely can help
Junior network engineer interview questions in the UK usually cover subnetting, the OSI model, VLANs, routing, DNS and DHCP, plus at least one troubleshooting scenario and a few behavioural questions. Prepare for the technical basics, but put most of your effort into explaining real problems you've solved. That's where beginners usually lose marks.
What does a junior network engineer interview look like?
Typically a phone or video screen, then a technical interview with one or two engineers. Some employers add a practical: subnetting on paper, a Packet Tracer task or a whiteboard diagram.
Interviewers want to know three things. Do you understand the fundamentals properly, beyond the textbook definitions? Can you troubleshoot calmly? And will you be careful on a live network? A junior who says "I'd check the change was approved and take a config backup first" will often beat a candidate who knows more commands.
Which fundamentals questions come up most?
"Explain the OSI model." Don't recite seven layers and stop. Give an example. A cable fault is layer 1, a VLAN issue is layer 2, a routing problem is layer 3, a blocked port is layer 4. That shows you use it to troubleshoot.
"What's the difference between a switch and a router?" Switches forward frames within a network using MAC addresses. Routers forward packets between networks using IP addresses. Mention layer 3 switches to show you know the line is blurry.
"Subnet 192.168.10.0/26 for me." Practise until it's automatic. Four subnets of 64 addresses, 62 usable hosts each. Know the network address, broadcast address and usable range without a calculator.
"What's a VLAN and why use one?" Logical separation of a switch into broadcast domains, for security, performance and organisation. Then explain trunking and 802.1Q tagging.
"How does DHCP work?" Discover, offer, request, acknowledge. Mention DHCP relay if the server's on another subnet.
"What happens when you type a website address into a browser?" A favourite. DNS lookup, ARP for the gateway, TCP handshake, TLS, HTTP request. Take your time and keep it in order.
Which routing and switching questions should you prepare?
"What's the difference between static and dynamic routing?" Static routes are configured by hand and don't adapt. Dynamic protocols like OSPF learn routes and react to failures.
"How does OSPF choose a path?" Lowest cost, based on interface bandwidth by default. Mention areas and why area 0 matters.
"What does spanning tree do?" Prevents switching loops by blocking redundant paths. Bonus points for mentioning rapid spanning tree and root bridge election.
"What's NAT and why do we use it?" Translating private addresses to public ones, mainly to conserve IPv4 addresses.
These all line up with the CCNA exam topics Cisco publishes, which cover network fundamentals, network access, IP connectivity, IP services, security fundamentals, and automation and programmability. If you've studied for the CCNA, you've covered most of the technical round.
How do you handle troubleshooting scenarios?
The classic: "A user says they can't get on the internet. What do you do?"
Work through it in order and say it out loud. Is the cable or Wi-Fi connected? Does the device have a valid IP address, or a 169.254 address suggesting DHCP failed? Can it ping its default gateway? Can it ping an external IP address? Does DNS resolve? Is anyone else affected? That last question tells you whether it's one device or a wider outage.
A follow-up often comes next: "Now it's the whole floor." That shifts you towards the access switch, its uplink, the DHCP scope and recent changes. Say you'd check the change log early. A surprising number of outages follow a change made the night before.
Interviewers are watching your method, not waiting for one correct answer. If you don't know something, say what you'd check next and who you'd escalate to.
What behavioural questions do they ask?
"Tell me about a time you fixed a difficult problem."
"Tell me about a mistake you made and what you learned."
"Describe a time you had to explain something technical to a non-technical person."
The National Careers Service recommends the STAR method for these: situation, task, action, result. Keep the setup short. Spend most of the time on what you did.
For example: "On a live network project, users in one office lost access to a shared drive after a change. I checked the switch config and found the new access port was on the wrong VLAN. I corrected it, confirmed with the users and updated the change record so the template was fixed." Short, specific, honest.
If you've never worked on a real network, these questions are hard. That's the strongest argument for getting real experience before you interview, even a few months of it.
How do you write an entry level network engineer CV?
Your CV gets you into the room, so it's worth getting right.
Profile. Two or three lines. What you're aiming for and what you bring. Skip "hard-working team player".
Certifications. Network+, CCNA and anything else relevant, with dates. Put them near the top for junior roles.
Experience. This is the section that decides it. List real network tasks with outcomes: "Configured VLANs and trunk ports on Cisco switches for a live office network" beats "knowledge of VLANs". Include placements, volunteer work and any network duties from support jobs.
Technical skills. Group them: routing and switching, protocols, tools (Wireshark, PuTTY, monitoring platforms), vendors.
Previous career. Don't hide it. Show transferable skills such as customer handling, process work and fault-finding.
Keep it to two pages. Tailor the top third to every application. If a job advert mentions Meraki or Fortinet and you've used either, make it visible.
For a view of the junior roles to target with that CV, see our junior network engineer guide.
Before you send it, ask someone technical to read it for ten minutes. Typos in IP addresses or vendor names look careless, and careless is the one thing a network team can't afford.
What should you ask at the end?
Ask about the network and the team, not the perks. What kit and vendors does the team use? How big is the estate? How are juniors trained, and who would I shadow? What does on-call look like? What would a good first six months look like?
How Experiencely can help
Experiencely's network engineering programme gives you real network work to talk about in interviews and put on your CV. Training covers A+, Network+, Security+, CCNA, ENCOR and ENARSI. You're placed on a live remote network project within 48 hours and work on it for about an hour a day over three months, alongside your current job, under real-world conditions. The programme costs £2,495. If you're not hired within 60 days of finishing, and you've met the conditions, you get your money back.
Frequently asked questions
What questions are asked in a junior network engineer interview?
Expect the OSI and TCP/IP models, subnetting, VLANs and trunking, the difference between switches and routers, routing protocols such as OSPF, DNS and DHCP, a troubleshooting scenario, and behavioural questions about real problems you've solved. Many interviewers ask you to subnet on the spot.
How should I answer network troubleshooting questions?
Work through the layers in order and say each step out loud. Check physical connectivity, then addressing, gateway, DNS, routing and firewall rules. Interviewers care about a calm, methodical approach and knowing when to escalate, as much as the final answer.
What should an entry level network engineer CV include?
A short profile, your certifications such as Network+ or CCNA, and an experience section built around real network tasks with outcomes. Include the kit and tools you've used, any live project or placement work, and transferable experience from previous jobs. Keep it to two pages.
What is the STAR method for interviews?
STAR stands for situation, task, action and result. The National Careers Service recommends it for answering behavioural questions fully. Keep the situation brief, spend most of the answer on what you did, and finish with a clear outcome and what you learned.
Sources
Figures are taken from the sources below. Salary ranges are indicative and individual offers vary. Last checked 9 November 2026.