<p>I am using Kubernetes with Minikube on a Windows 10 Home machine to &quot;host&quot; a gRPC service. I am working on getting Istio working in the cluster and have been running into the same issue over and over and I cannot figure out why. The problem is that once everything is up and running, the Istio gateway uses IPv6, seemingly for no reason at all. IPv6 is even disabled on my machine (via regedit) and network adapters. My other services are accessible from IPv4. Below are my steps for installing my environment:</p>
<pre class="lang-sh prettyprint-override"><code>minikube start
kubectl create namespace abc
kubectl apply -f service.yml -n abc
kubectl apply -f gateway.yml
istioctl install --set profile=default -y
kubectl label namespace abc istio-injection=enabled
</code></pre>
<p>Nothing is accessible over the network at this point, until I run the following in its own terminal:</p>
<pre class="lang-sh prettyprint-override"><code>minikube tunnel
</code></pre>
<p>Now I can access the gRPC service directly using IPv4: <code>127.0.0.1:5000</code>. However, accessing the gateway is inaccessible from <code>127.0.0.1:443</code> and instead is only accessible from <code>[::1]:443</code>.</p>
<p>Here is the service.yml:</p>
<pre class="lang-yaml prettyprint-override"><code>apiVersion: v1
kind: Service
metadata:
  name: account-grpc
spec:
  ports:
  - name: grpc
    port: 5000
    protocol: TCP
    targetPort: 5000
  selector:
    service: account
    ipc: grpc
  type: LoadBalancer
---
apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    service: account
    ipc: grpc
  name: account-grpc
spec:
  replicas: 1
  selector:
    matchLabels:
      service: account
      ipc: grpc
  template:
    metadata:
      labels:
        service: account
        ipc: grpc
    spec:
      containers:
        - image: account-grpc
          name: account-grpc
          imagePullPolicy: Never
          ports:
            - containerPort: 5000
</code></pre>
<p>Here is the gateway.yml</p>
<pre class="lang-yaml prettyprint-override"><code>apiVersion: networking.istio.io/v1alpha3
kind: Gateway
metadata:
  name: gateway
spec:
  selector:
    istio: ingressgateway
  servers:
  - port:
      number: 443
      name: grpc
      protocol: GRPC
    hosts:
    - &quot;*&quot;
---
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: virtual-service
spec:
  hosts:
  - &quot;*&quot;
  gateways:
  - gateway
  http:
  - match:
    - uri:
        prefix: /account
    route:
    - destination:
        host: account-grpc
        port:
          number: 5000
</code></pre>
<p>And here are the results of <code>kubectl get service istio-ingressgateway -n istio-system -o yaml</code>:</p>
<pre class="lang-yaml prettyprint-override"><code>apiVersion: v1
kind: Service
metadata:
  annotations:
    kubectl.kubernetes.io/last-applied-configuration: ...
  creationTimestamp: &quot;2021-08-27T01:21:21Z&quot;
  labels:
    app: istio-ingressgateway
    install.operator.istio.io/owning-resource: unknown
    install.operator.istio.io/owning-resource-namespace: istio-system
    istio: ingressgateway
    istio.io/rev: default
    operator.istio.io/component: IngressGateways
    operator.istio.io/managed: Reconcile
    operator.istio.io/version: 1.11.1
    release: istio
  name: istio-ingressgateway
  namespace: istio-system
  resourceVersion: &quot;4379&quot;
  uid: b4db0e2f-0f45-4814-b187-287acb28d0c6
spec:
  clusterIP: 10.97.4.216
  clusterIPs:
  - 10.97.4.216
  externalTrafficPolicy: Cluster
  ipFamilies:
  - IPv4
  ipFamilyPolicy: SingleStack
  ports:
  - name: status-port
    nodePort: 32329
    port: 15021
    protocol: TCP
    targetPort: 15021
  - name: http2
    nodePort: 31913
    port: 80
    protocol: TCP
    targetPort: 8080
  - name: https
    nodePort: 32382
    port: 443
    protocol: TCP
    targetPort: 8443
  selector:
    app: istio-ingressgateway
    istio: ingressgateway
  sessionAffinity: None
  type: LoadBalancer
status:
  loadBalancer:
    ingress:
    - ip: 127.0.0.1
</code></pre>

<p>Changing the port number to port 80 resolved my issue. The problem was that my gRPC service was not using HTTPS. Will return if I have trouble once I change the service to use HTTPS.</p>
