 to debug Envoy you need to understand Envoy clusters/listeners/routes/endpoints and how they all interact.
We will use the <code>proxy-config</code> command with the <code>-o json</code> and filtering flags to follow Envoy as it determines where
to send a request from the <code>productpage</code> pod to the <code>reviews</code> pod at <code>reviews:9080</code>.</p><ol><li><p>If you query the listener summary on a pod you will notice Istio generates the following listeners:</p><ul><li>A listener on <code>0.