a href=https://istio.io/v1.6/docs/reference/config/policy-and-telemetry/metrics>default
metrics</a> are augmented with
explicit labels to capture blocked and passthrough external service traffic.
This blog will cover how you can use these augmented metrics to monitor all
external service traffic.</p><p>The Istio control plane configures the sidecar proxy with
predefined clusters called BlackHoleCluster and Passthrough which block or
allow all traffic respectively. To understand these clusters, let&rsquo;s s