How does kubernetes namespaces affect networking?

When you create a namespace with the basic configuration, it does not prevent connectivity from other namespaces. You can connect to Services in other namespaces using the DNS:  ..svc.cluster.local.    So, if you exec into a container in the default namespace and want to access a service in the test namespace, you can connect like such:  curl -i http://hello-svc.test.svc.cluster.local:8080.     If you wanted to connect to the hello-svc in the default namespace, you can just reference the service name curl -I http://hello-svc.

For your information, if you are looking for how to restrict the networking, you may want to look into the network policy for more details. (https://kubernetes.io/docs/concepts/services-networking/network-policies/)