-N ISTIO_POSTRT
-A POSTROUTING -j ISTIO_POSTRT
-A ISTIO_POSTRT -m owner --socket-exists -p tcp -m set --match-set istio-inpod-probes-v4 dst -j SNAT --to-source 169.254.7.127
COMMIT
* nat
-N ISTIO_POSTRT
-A POSTROUTING -j ISTIO_POSTRT
-A ISTIO_POSTRT -m owner --socket-exists -p tcp -m set --match-set istio-inpod-probes-v6 dst -j SNAT --to-source fd16:9254:7127:1337:ffff:ffff:ffff:ffff

* nat
-N ISTIO_POSTRT
-A POSTROUTING -j ISTIO_POSTRT
-A ISTIO_POSTRT -m owner --socket-exists -p tcp -m set --match-set istio-inpod-probes-v4 dst -j SNAT --to-source 169.254.7.127

      "plugin_log_level": "info",
      "policy": {
        "type": "k8s"
      },
      "type": "calico"
    },
    {
      "capabilities": {
        "portMappings": true
      },
      "snat": true,
      "type": "portmap"
    },
    {
      "ambient_enabled": false,
      "cni_agent_run_dir": "/tmp",
      "dns": {},
      "exclude_namespaces": [
        "istio-system"
      ],

	iptablesBuilder.AppendRuleV4(
		iptableslog.UndefinedCommand, ChainHostPostrouting, iptablesconstants.NAT,
		"-m", "owner",
		"--socket-exists",
		"-p", "tcp",
		"-m", "set",
		"--match-set", fmt.Sprintf(ipset.V4Name, ProbeIPSet),
		"dst",
		"-j", "SNAT",
		"--to-source", hostSNATIP.String(),
	)

)

const (
	// to reliably identify kubelet healthprobes from inside the pod (versus standard kube-proxy traffic,
	// since the IP is normally the same), we SNAT identified host probes in the host netns to a fixed
	// APIPA/"link-local" IP.
	//
	// It doesn't matter what this IP is, so long as it's not routable and doesn't collide with anything else.
	//

|--------------------|-----------------|-----------------------------------------------------------------------------------------------------------------------------------------------|
| HOST_PROBE_SNAT_IP | "169.254.7.127" | Applied to SNAT host probe packets, so they can be identified/skipped podside. Any link-local address in the 169.254.0.0/16 block can be used |