10 Common Kubernetes Network Errors Explained (DNS, Services, Ingress & Fixes) [2026 Guide]

Last Updated: January 09 2026

Kubernetes network errors are the among the most challenging issues faced when working on the orchestration platform with the containerized applications. These errors can prevent pods from communicating with each other, Can block the external traffic, or stop the services from working properly. In this article, we will explore the 10 Common Kubernetes Network Errors, how to debug them, and provide practical solutions to fix them permanently.

Understanding Kubernetes networking always an essential part for smooth deployments. Let’s dive into the world of Kubernetes network troubleshooting and learn how to solve these problems step by step.

What is Kubernetes Networking?

Before we proceed with the networking errors and there fixes, let’s understand how Kubernetes networking works.

Kubernetes networking connects all the components in the cluster:

• Pods need to talk to other pods in the cluster.
• Services route the traffic to the right pods.
• Ingress handles all the external traffic coming into the cluster from outside.
• Network policies control which pods can communicate within the cluster.

The Four Basic Rules of Kubernetes Networking

1. Pod-to-Pod communication: Every pod can talk to other pod in the cluster
2. Node-to-Pod communication: Nodes can communicate with all pods in the cluster
3. Pod IP addresses: Each pod gets its own IP address which are unique
4. Service discovery: Services provide the stable endpoints to pods

When any of these rules are broken, you always get network errors.

Common Kubernetes Network Errors and Their Meaning

1. Connection Refused Errors

Error: dial tcp 10.244.1.5:8080: connect: connection refused

This means that pod is running but application inside the pod is not listening on the expected port.

2. Connection Timeout Errors

Error: dial tcp 10.244.1.5:8080: i/o timeout

This is related with the network policy or firewall issue.

3. No Route to Host Errors

Error: dial tcp 10.244.1.5:8080: no route to host

It means that there is no network path to reach the destination pod.

4. DNS Resolution Failures

Error: lookup mysvc.default.svc.cluster.local: no such host

DNS is not working properly in the cluster.

5. Service Unavailable Errors

Error: Service Unavailable (503)

Service is present on the cluster but there are no healthy pods behind it.

Part 1: The Story of Network Troubleshooting

Monday Morning, 9:30 AM

Max is a DevOps engineer. He just deployed a new microservice to production cluster. Everything looked good during testing, but now the users are reporting errors at large scale. His monitoring dashboard shows red alerts everywhere.

He opens his terminal and types:

kubectl get pods

All pods show Running status. But the application is not working. This is a network problem.

The Troubleshooting Begins

Max knows that in Kubernetes, when pods are running ok but not working, it’s usually a networking issue. He starts his investigation using the standard debugging steps.

Essential Commands to Debug Kubernetes Network Errors

Let’s follow Max debugging process step by step.

Step 1: Pod Status and IP Addresses

kubectl get pods -o wide

This shows:

NAME                     READY   STATUS    IP            NODE
frontend-abc123          1/1     Running   10.244.1.5    node-1
backend-xyz789           1/1     Running   10.244.2.8    node-2

Both pods are running and have IP addresses assigned. No bad sign here.

Step 2: Testing Pod-to-Pod Connectivity

kubectl exec -it frontend-abc123 -- ping 10.243.2.8

If ping doesn’t work, there’s a network connectivity problem between pods.

Step 3: Checking Service Configuration

kubectl get services
kubectl describe service backend-service

Look at the following parameters:

• Selector: Does it match your pod labels?
• Port: Is this the correct port?
• Endpoints: Are there any endpoints been listed?

Step 4: Checking Service Endpoints

kubectl get endpoints backend-service

If this shows no IP addresses, your service is not connected to any of the pods in cluster.

Step 5: Testing DNS Resolution

kubectl exec -it myapp-abcd123 -- nslookup backend-service

This should always return the service IP address. If this fails, DNS is broken.

Step 6: Check Network Policies

kubectl get networkpolicies
kubectl describe networkpolicy polic-name

Network policies can also block traffic between pods.

Step 7: Check pod Logs for Network Errors

kubectl logs abc-abc123
kubectl logs def-xyz789

Look for connection errors, timeout messages, or DNS failures.

10 Most Common Kubernetes Network Problems and their fixes

Problem #1: Service Cannot Find Pods (No Endpoints)

What happens: You create a service but it has no endpoints. Traffic cannot reach to any pods.

How to identify:

kubectl get endpoints <service-name>

Shows empty or no IP addresses.

Root cause: Service selector doesn’t match pod labels.

How to fix:

Check your service selector:

kubectl describe service <service-name>

Check your pod labels:

kubectl get pods --show-labels

Make sure they match. Fix your service YAML:

apiVersion: v1
kind: Service
metadata:
  name: backend-service
spec:
  selector:
    app: backend      <--# This must match pod labels
    tier: api
  ports:
  - protocol: TCP
    port: 80
    targetPort: 8080

Problem #2: Connection Refuse – Wrong Port Configuration

What happens: Service exists, pods are running, but connections refused.

How to identify:

kubectl logs <pod-name>

Look for “connection refused” errors.

Root cause: Application listening on a different port than what the service is targeting.

How to fix:

Check what port your application is using:

kubectl exec -it <pod-name> -- netstat -tulpn

Update your service to use the correct port:

apiVersion: v1
kind: Service
metadata:
  name: myapp-service
spec:
  selector:
    app: myapp
  ports:
  - protocol: TCP
    port: 80           # Port that service exposes
    targetPort: 8080   # Port that container listens on

Problem #3: DNS Not Working – Cannot Resolve Service Names

What happens: Pods cannot resolve service names to IP addresses.

How to identify:

kubectl exec -it <pod-name> -- nslookup kubernetes.default

If it fails, CoreDNS is not working.

Root cause: CoreDNS pods are not running or misconfigured.

How to fix:

Check CoreDNS status:

kubectl get pods -n kube-system -l k8s-app=kube-dns

If CoreDNS pods are not running:

kubectl rollout restart deployment/coredns -n kube-system

Check CoreDNS logs:

kubectl logs -n kube-system -l k8s-app=kube-dns

Problem #4: Network Policy Blocking the Traffic

What happens: Pods cannot communicate even though everything is configured correctly.

How to identify:

kubectl get networkpolicies --all-namespaces

Root cause: A network policy denying the traffic.

How to fix:

First, understand the existing policies:

kubectl describe networkpolicy <policy-name>

Create or update network policy to allow traffic:

apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: allow-frontend-to-backend
spec:
  podSelector:
    matchLabels:
      app: backend
  policyTypes:
  - Ingress
  ingress:
  - from:
    - podSelector:
        matchLabels:
          app: frontend
    ports:
    - protocol: TCP
      port: 8080

Problem #5: Pod Cannot Reach the External Services

What happens: Pods can communicate internally but can’t reach the external APIs or databases.

How to identify:

kubectl exec -it <pod-name> -- curl https://www.bing.com

If this fails, external connectivity is broken.

Root cause: NAT is not working, firewall rules, or no internet gateway available.

How to fix:

Check if the DNS works for external domains:

kubectl exec -it <pod-name> -- nslookup bing.com

Check cluster’s NAT configuration (cloud provider specific).

Problem #6: Ingress Not Routing Traffic

What happens: External users are not able to access your application through ingress.

How to identify:

kubectl get ingress
kubectl describe ingress <ingress-name>

Check if ingress has IP address assigned.

Root cause: Ingress controller are not running, or incorrect ingress rules.

How to fix:

Check ingress controller pods present on the cluster:

kubectl get pods -n ingress-nginx

If not installed, install an ingress controller:

kubectl apply -f https://raw.githubusercontent.com/kubernetes/ingress-nginx/controller-v1.7.1/deploy/static/provider/cloud/deploy.yaml

Example correct ingress configuration:

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: myapp-ingress
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: /
spec:
  ingressClassName: nginx
  rules:
  - host: myapp.example.com
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: myapp-service
            port:
              number: 80

Problem #7: CNI Plugin Failures

What happens: Pods stuck in ContainerCreating state, network not ready.

How to identify:

kubectl describe pod <pod-name>

Look for “Network plugin returns error” in events.

Root cause: CNI plugin is not working.

How to fix:

Check CNI plugin pods (example for Calico):

kubectl get pods -n kube-system | grep calico

Restart CNI pods:

kubectl delete pod -n kube-system -l k8s-app=calico-node

Check CNI configuration:

cat /etc/cni/net.d/*

Problem #8: Service Type LoadBalancer Not Getting External IP

What happens: LoadBalancer service in pending state, no external IP address assigned.

How to identify:

kubectl get service <service-name>

Shows EXTERNAL-IP as <pending>.

Root cause: Cloud provider doesn’t support LoadBalancer, or quota exceeded.

How to fix:

For cloud providers (AWS, GCP, Azure), check:

• Load balancer quota not exceeded
• Correct cloud provider configuration
• IAM permissions for creating load balancers

Alternative: Use NodePort or Ingress instead:

apiVersion: v1
kind: Service
metadata:
  name: myapp-service
spec:
  type: NodePort -->   # Changed from LoadBalancer
  selector:
    app: myapp
  ports:
  - protocol: TCP
    port: 80
    targetPort: 8080
    nodePort: 30080  # Access via <node-ip>:30080

Problem #9: Cross-Namespace Communication Failed

What happens: Pods in different namespaces in cluster cannot communicate with each other.

How to identify: Test connection from one namespace to another:

kubectl exec -it <pod-name> -n namespace01 -- curl http://service-name.namespace02.svc.cluster.local

Root cause: Network policy restricting cross-namespace traffic.

How to fix:

Allow the cross-namespace communication:

apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: allow-cross-namespace
  namespace: namespace2
spec:
  podSelector:
    matchLabels:
      app: backend
  policyTypes:
  - Ingress
  ingress:
  - from:
    - namespaceSelector:
        matchLabels:
          name: namespace1

Use full DNS name when accessing services across namespaces:

http://service-name.namespace.svc.cluster.local

Problem #10: High Network Latency Between Pods

What happens: Pods can communicate but the response times is slow.

How to identify:

kubectl exec -it <pod-name> -- ping <target-pod-ip>

Check for the high ping times (over 200ms for the cluster).

Root cause: Pods scheduled on different nodes, network congestion, or the CNI issues.

How to fix:

Use pod affinity to keep related pods on same node:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: frontend
spec:
  template:
    spec:
      affinity:
        podAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
          - labelSelector:
              matchLabels:
                app: backend
            topologyKey: kubernetes.io/hostname
      containers:
      - name: frontend
        image: frontend:latest

Check network plugin performance and consider upgrading.

Advanced Kubernetes Network Debugging Techniques

tcpdump to Capture Network Traffic

kubectl exec -it <pod-name> -- tcpdump -i eth0 -n

This shows all network packets, which is helpful for deep debugging.

Check for iptables Rules (for advanced users)

kubectl exec -it <pod-name> -- iptables -L -n -v

This shows firewall rules that might be blocking traffic.

Testing with Debug Pod

Create a debug pod with network tools:

apiVersion: v1
kind: Pod
metadata:
  name: network-debug
spec:
  containers:
  - name: debug
    image: nicolaka/netshoot
    command: ["sleep", "3600"]

Then use it for testing:

kubectl exec -it network-debug -- curl http://service-name
kubectl exec -it network-debug -- dig service-name.namespace.svc.cluster.local
kubectl exec -it network-debug -- traceroute service-ip

Check Node Network Configuration

If pods cannot communicate across nodes:

kubectl get nodes -o wide

SSH into node and check:

ip route
iptables -L
systemctl status kubelet

Kubernetes Network Troubleshooting Checklist

When you face network issues, go through this checklist:

Basic Checks

• [ ] Are all pods in Running state?
• [ ] Do pods have the IP addresses assigned?
• [ ] Does the service exist and have correct selectors?
• [ ] Does the service have endpoints?
• [ ] Can you ping the pod IP directly?

DNS Checks

• [ ] Can pods resolve kubernetes.default?
• [ ] Can pods resolve service names?
• [ ] Are CoreDNS pods running?
• [ ] Is /etc/resolv.conf correct in pods?

Service Checks

• [ ] Does service selector match pod labels?
• [ ] Is targetPort correct?
• [ ] Are pods healthy and ready?
• [ ] Is service type correct (ClusterIP/NodePort/LoadBalancer)?

Network Policy Checks

• [ ] Are there any network policies in the namespace?
• [ ] Do network policies allow the required traffic?
• [ ] Are ingress and egress rules correct?

CNI Plugin Checks

• [ ] Are CNI plugin pods running?
• [ ] Check CNI logs for errors
• [ ] Is CNI configuration correct?

Prevention Best Practices for Kubernetes Networking

1. Use Proper Labels and Selectors

Always use consistent labeling:

labels:
  app: myapp
  tier: frontend
  version: v1

2. Test Services Before Production

# Create a test pod
kubectl run test-pod --image=busibox -it --rm -- sh

# Inside the pod, test the service
wget -O- http://servce-name:80

3. Monitor Network Health

Set up monitoring for:

• Pod-to-pod latency
• Service endpoint availability
• DNS query success rate
• Network policy violation

4. Use Network Policies Wisely

Start with permissive policies, then restrict:

# Default deny all
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: default-deny-all
spec:
  podSelector: {}
  policyTypes:
  - Ingress
  - Egress

# Then explicitly allow what's needed

---

Common Network Error Messages and Quick Solutions

FAQ

How do I check if my cluster networking is working properly ?

# Check CNI pods
kubectl get pods -n kube-system | grep -E 'calico|flannel|weve|cilium'

# Check the CoreDNS
kubectl get pods -n kube-system -l k8s-app=kube-dns

# Test the pod-to-pod communication
kubectl run tes1 --image=busybox -- sleep 3600
kubectl run tes2 --image=busybox -- sleep 3600
kubectl exec tes1 -- ping <tes2-ip>

What is the difference between ClusterIP, NodePort, and LoadBalancer?

• ClusterIP: Internal only, pods can access within cluster
• NodePort: Accessible from outside of cluster via node-ip:port
• LoadBalancer: Gets external IP from the cloud provider

Why can’t my pod resolve DNS?

Check:

1. If CoreDNS pods are running
2. /etc/resolv.conf in pod is correct or not
3. Network policy not blocking the DNS port 53

Conclusion:

Kubernetes networking can seem very complex, but with the right approach, most network errors are easy to fix. Remember these following key points:

1. Start with basics – Check if pods are running and have IPs
2. Verify services – Make sure selectors match and endpoints exist
3. Test connectivity – Use exec to test from inside pods
4. Check DNS – Many issues are DNS-related
5. Review network policies – They might be blocking traffic
6. Monitor continuously – Catch network issues early

The debugging commands which we covered will always help you solve 90% of network problems:

• kubectl get pods -o wide
• kubectl describe service
• kubectl get endpoints
• kubectl exec -it <pod> -- curl/ping
• kubectl logs

Practice these commands, understand your cluster’s network architecture, and you’ll become a Kubernetes networking expert.

Additional Resources

• Kubernetes Official Networking Documentation
• CNI Plugin Documentation (Calico, Flannel, Cilium)
• Service Mesh Solutions (Istio, Linkerd) for advanced networking

Have you faced a unique Kubernetes network error? Please Share your experience in the comments below and let me know if yo like this artilce as your feedback will motivate me to write more articles like this. Let’s learn Kubernetes networking together.

Keywords: Kubernetes network errors, kubectl networking, Kubernetes DNS, pod connectivity, service endpoints, network policy, Kubernetes troubleshooting, CNI plugin, ingress errors, CoreDNS, Kubernetes networking guide