This message occurs for services of type ExternalName when the port doesn’t follow Istio service port naming convention, the port is unnamed or the port is named tcp.


You will receive this message:

Warning [IST0150] (Service nginx.default) Port name for ExternalName service is invalid. Proxy may prevent tcp named ports and unmatched traffic for ports serving TCP protocol from being forwarded correctly.

when your cluster has the following service:

apiVersion: v1
kind: Service
  name: nginx
  externalName: nginx.example.com
  - name: tcp
    port: 443
    protocol: TCP
    targetPort: 443
  type: ExternalName

In this example, the port name tcp follows the syntax: name: <protocol>. However, for ExternalName services, there is no service IP defined, so the SNI field is needed for routing.

How to resolve

  • If you have an ExternalName service type, and the protocol is TCP, rename the port to <protocol>[-<suffix>] or <protocol> where protocol is https or tls. To learn more, review docs on explicit protocol selection.