ALB · Security Groups · Intermediate
The one-way load balancer
Load-balancer requests time out although instances answer locally.
INITIAL ALERT
Load-balancer requests time out although instances answer locally.
You are primary on-call. Establish the failure domain, protect healthy capacity, and choose the safest next action.
The listener is active and the target process is bound to the correct port.
The decisive evidence and solution remain locked inside the simulation.WHAT THIS TESTS
Production judgment across ALB · Security Groups.
Networking failures often leave every individual component looking healthy. Strong responders compare the client path, control-plane configuration, and known-good traffic before changing production.
- 01Trace traffic across layered AWS controls
- 02Separate DNS, routing, and target failures
- 03Recover connectivity without creating drift
SIMULATION STRUCTURE
Four evidence layers. No answer shown here.
The full exercise unlocks each layer as you commit to decisions.
Alert
Confirm the reported symptom and customer impact.
Baseline
Compare the failing path with a known-good condition.
Finding
Identify the evidence that separates plausible causes.
Change
Choose a controlled recovery and a durable prevention step.
Can you make the call without seeing the solution?
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