Practice the incident, then explain your decisions.
Preparation for a network engineering role should combine technical evidence with clear communication.
Use a six-part narrative
Describe the symptom, observation, hypothesis, test, root cause, and remediation. Keep facts separate from guesses and say what would change your mind.
Work within the constraint
A production incident rarely allows a full redesign. Preserve the topology, identify the faulty decision, and make a minimal repair.
Review the postmortem
After solving the lab, compare your investigation with the reference approach. Identify one command you could have skipped and one verification you should have added. Company-specific assessment modes are planned.
Going in circles
Denver branch. Three core routers form a routed triangle between separate client and service edges. Addresses in the lower half of the primary service subnet fail, while .200 responds. The secondary service is unaffected. Investigate the two service networks from R1: 10.201.192.0/24 to 10.201.200.0/24 (TCP/443), and 10.201.193.0/24 to 10.201.201.0/24 (TCP/8443).
Link addressing (5)
- R1 R2
10.201.208.0/30 - R2 R4
10.201.209.0/30 - R2 R3
10.201.210.0/30 - R3 R4
10.201.211.0/30 - R4 R5
10.201.212.0/30
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