How to DENY all Ingress UDP using Network Policies in Kubernetes

Question

I am new to configuring network policies in k8s. I have to make a change in production which I cant test. Basically we need to block all UDP traffic going to the pods in a specific namespace. Would the below work?

apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: deny-all-udp
  namespace: foxden-loadtest
spec:
  podSelector: {}
  policyTypes:
  - Ingress
  ingress:
    ports:
    - protocol: UDP

Answer 1

Try this example

apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: ingress-allow-tcp only
spec:
  podSelector: {}
  policyTypes:
  - Ingress
  ingress:
  - ports:
    - port: 80
      protocol: TCP

Other all traffic will get blocked. Only TCP will work

policyTypes: ["ingress"] indicates that this policy enforces policies for the ingress traffic.

inress: [] empty rule set does not whitelist any traffic, therefore all ingress traffic is blocked.

Example : https://github.com/ahmetb/kubernetes-network-policy-recipes/blob/master/11-deny-egress-traffic-from-an-application.md