Network policies
As we already mentioned, OpenShift uses an SDN, and preferably, the network traffic control should be done using the features the cluster provides itself. In our experience, having implemented OpenShift in many organizations, we have often heard doubts regarding how to control network traffic within the cluster, as most customers are used to doing it by using regular firewall devices. In this section, we will walk you through how to control network traffic to be able to allow or deny network traffic as needed. Before giving you some options to do that, we first need to differentiate the different traffic directions that we have in a cluster.
North-south traffic
OpenShift has been designed to cover the most common scenarios, even regarding networking. When an incoming connection comes from outside the cluster to an application, it is possible to control network traffic into the cluster using an external firewall and/or the OpenShift Ingress solution.
