steners are set up for each IP:Port pair in the headless service.</p><div><aside class="callout warning"><div class=type><svg class="large-icon"><use xlink:href="/v1.12/img/icons.svg#callout-warning"/></svg></div><div class=content>Without Istio, the <code>ports</code> field of a headless service is not strictly required because requests go directly to pod IPs, which can accept traffic on all ports.
However, with Istio the port must be declared in the Service, or it will <a href=#unmatched-traffic>not be ma