Kubernetes Networking Overview¶

Kubernetes networking looks complicated because several layers cooperate. Each layer has one job, and most problems are easier once you know which layer you are in.

The network model¶

Every Pod gets its own IP address.
Pods can talk to all other Pods without NAT.
Node agents can talk to all Pods on their node.
A Service gives a stable virtual IP and DNS name to a changing set of Pods.

The layers¶

 Client
   │
   ▼
 Gateway / Ingress / LoadBalancer      external traffic in
   │
   ▼
 Service (ClusterIP)  ◄── DNS (CoreDNS)  stable name and virtual IP
   │
   ▼
 kube-proxy or eBPF rules              picks a healthy endpoint
   │
   ▼
 Pod IP  ◄── CNI plugin                pod-to-pod across nodes

Layer	Handled by	Read
Pod-to-Pod	CNI plugin	Pod Networking and CNI
Names	CoreDNS	DNS
Stable access	Services	Services
External traffic	Gateway API / Ingress	Gateway API and Ingress
Isolation	NetworkPolicy	Network Policies

Go deeper¶

For a longer walkthrough, read the article Kubernetes Networking Deep Dive.

When something is broken, go straight to Services and DNS troubleshooting.