I am trying to understand Networking policy for Kubernetes services.

Have few services running inside kubernetes and few running outside kubernetes. Would like to restrict access for each service.

Say, Service A, B and C are running inside kubernetes. Service D, E & F are running outside Kubernetes.

Looking forward to restrict service A to be accessed only by Service B(Running inside Kubernetes) & Service F(Running outside Kubernetes). Meaning b/w services inside the cluster and outside traffic to cluster vis ingress.

Came across Networking policyTypes Ingress & Egress. Rules can be of ipBlock, namespaceSelector or podSelector.

Do i need to route services running inside the cluster also to go via ingress for restriction?

Any example config for b/w services in kubenrtes and extenral service to service running in kubernetes?

Can we have all these internal & external rules in a single policy file?

Is it possible to update the policy at run time without affecting the existing traffic?

Thanks