AWS EKS docker changes port to random

General Discussions
1

K8s version: 1.29
Aws CNI 1.18.1

Expected behavior

Outgoing port is the same as the selected by the application

Actual behavior

Docker seems to select a random source port ignoring the network-host setting.

Additional Information

Steps to reproduce the behavior

Install kamailio
Receive an INVITE on one port and forward it on a different port.
The actual port going out is NOT the one selected by the application.

The pod is running in hostNetwork: true mod:


containers:
image: myimage    imagePullPolicy: Always
    name: sip-proxy
    resources: {}
    securityContext:
      privileged: true
    terminationMessagePath: /dev/termination-log
    terminationMessagePolicy: File
    volumeMounts:
mountPath: /var/run/secrets/kubernetes.io/serviceaccount      name: kube-api-access-84tdr
      readOnly: true
  dnsPolicy: ClusterFirstWithHostNet
  enableServiceLinks: true
  hostNetwork: true
  imagePullSecrets:
name: regcred  nodeName: ip-10-1-2-36.ec2.internal
  nodeSelector:
    application: proxy
  preemptionPolicy: PreemptLowerPriority
  priority: 0
  restartPolicy: Always
  schedulerName: default-scheduler
  securityContext: {}
  serviceAccount: default
  serviceAccountName: default
  terminationGracePeriodSeconds: 30

I’m positive is selecting the socket properly, is there any setting in the network/container side regarding using random on outbound? BTW the image does NOT exposes the 5160 port, but i understand that doesn’t matter if i’m running it in hostNetwork mode?

Thanks again!