A core router change you made during a maintenance window caused an outage. How would you handle the rollback and the conversation afterwards?

What the interviewer is looking for

• This question tests composure under pressure. Handles outages and failed changes calmly, follows rollback plans, and takes responsibility openly.
• What to bring out: Follows a prepared rollback, communicates status, restores service before investigating, owns the mistake, and improves the change process.
• Expect a follow-up like: What should a good change plan include before you touch a core device?

Another way it may be asked: You make a planned change late at night and the network goes down. What do you do then and the next morning?

A structure to follow: STAR, with the weight on Action and Result

1. Step 1

   Situation

   One or two sentences: where, when and what was at stake. Pick a real example you were close to.

2. Step 2

   Task

   What you personally were responsible for. Say "I", not only "we", so the composure under pressure you showed is visible.

3. Step 3

   Action

   The two or three things you did and why you chose them over the alternatives. This should be about half your answer.

4. Step 4

   Result

   What changed, in your own measure of it, and what you would do differently. Only use numbers you can stand behind.

This is guidance on shape, not a script. Use your own real experience and facts; never invent details to fill a gap. See the STAR guide and answer frameworks.

Common slips

• Describing what the team did without saying what you did.
• Choosing an example with no clear outcome, or one you cannot answer detailed questions about.
• Ending on the action and skipping the result and what you learned.

How to practise it

Write two bullet points for each STAR letter, then say the answer aloud in about two minutes.

Related questions

• Explain what happens on the network, step by step, when someone types a website address into their browser and presses enter.
• What is a VLAN, and why would an office separate its traffic into different VLANs?
• A user says they cannot reach the internet, but their coworker sitting next to them can. How would you troubleshoot it?
• When would you choose OSPF versus BGP, and what problems have you seen with either in practice?
• How would you set up firewall rules and segmentation for a network with guest wireless, office staff and payment terminals?

Browse all questions