You can create a "default" isolation policy for a namespace by creating a NetworkPolicy that selects all pods but does not allow any ingress traffic to those pods.

---

apiVersion: networking.k8s.io/v1

kind: NetworkPolicy

metadata:

name: default-deny-ingress

spec:

podSelector: {}

policyTypes:

- Ingress

You can create a "default" egress isolation policy for a namespace by creating a NetworkPolicy that selects all pods but does not allow any egress traffic from those pods.

---

apiVersion: networking.k8s.io/v1

kind: NetworkPolicy

metadata:

name: allow-all-egress

spec:

podSelector: {}

egress:

- {}

policyTypes:

- Egress

Default deny all ingress and all egress trafficYou can create a "default" policy for a namespace which prevents all ingress AND egress traffic by creating the following NetworkPolicy in that namespace.

---

apiVersion: networking.k8s.io/v1

kind: NetworkPolicy

metadata:

name: default-deny-all

spec:

podSelector: {}

policyTypes:

- Ingress

- Egress

This ensures that even pods that aren't selected by any other NetworkPolicy will not be allowed ingress or egress traffic.