end the traffic to the
original destination i.e. passthrough.</p><p>Similar to the BlackHoleCluster, for every port/protocol based listener the
virtual route configuration is augmented to add the PassthroughCluster as the
default route:</p><pre><code class=language-json data-expandlinks=true data-repo=istio>{
  &#34;name&#34;: &#34;allow_any&#34;,
  &#34;domains&#34;: [
    &#34;*&#34;
  ],
  &#34;routes&#34;: [
    {
      &#34;match&#34;: {
        &#34;prefix&#34;: &#34;/&#34;
      },
      &#34;route&#