--- assignees: - thockin - caseydavenport - danwinship title: Network Policies redirect_from: - "/docs/user-guide/networkpolicies/" - "/docs/user-guide/networkpolicies.html" --- {% capture overview %} A network policy is a specification of how groups of pods are allowed to communicate with each other and other network endpoints. `NetworkPolicy` resources use labels to select pods and define whitelist rules which allow traffic to the selected pods in addition to what is allowed by the isolation policy for a given namespace. {% endcapture %} {% capture body %} ## The `NetworkPolicy` Resource See the [api-reference](/docs/api-reference/networking/v1/definitions/#_v1_networkpolicy) for a full definition of the resource. An example `NetworkPolicy` might look like this: ```yaml apiVersion: networking/v1 kind: NetworkPolicy metadata: name: test-network-policy namespace: default spec: podSelector: matchLabels: role: db ingress: - from: - namespaceSelector: matchLabels: project: myproject - podSelector: matchLabels: role: frontend ports: - protocol: tcp port: 6379 ``` *POSTing this to the API server will have no effect unless your chosen networking solution supports network policy.* __Mandatory Fields__: As with all other Kubernetes config, a `NetworkPolicy` needs `apiVersion`, `kind`, and `metadata` fields. For general information about working with config files, see [here](/docs/user-guide/simple-yaml), [here](/docs/user-guide/configuring-containers), and [here](/docs/user-guide/working-with-resources). __spec__: `NetworkPolicy` [spec](https://github.com/kubernetes/kubernetes/tree/{{page.githubbranch}}/docs/devel/api-conventions.md#spec-and-status) has all the information needed to define a particular network policy in the given namespace. __podSelector__: Each `NetworkPolicy` includes a `podSelector` which selects the grouping of pods to which the policy applies. Since `NetworkPolicy` currently only supports definining `ingress` rules, this `podSelector` essentially defines the "destination pods" for the policy. The example policy selects pods with the label "role=db". An empty `podSelector` selects all pods in the namespace. __ingress__: Each `NetworkPolicy` includes a list of whitelist `ingress` rules. Each rule allows traffic which matches both the `from` and `ports` sections. The example policy contains a single rule, which matches traffic on a single port, from either of two sources, the first specified via a `namespaceSelector` and the second specified via a `podSelector`. So, the example NetworkPolicy: 1. allows connections to tcp port 6379 of "role=db" pods in the "default" namespace from any pod in the "default" namespace with the label "role=frontend" 2. allows connections to tcp port 6379 of "role=db" pods in the "default" namespace from any pod in a namespace with the label "project=myproject" {% endcapture %} {% capture whatsnext %} * For configuration instructions, see [Configuring Namespace Isolation](/docs/tasks/administer-cluster/configure-namespace-isolation). * For more NetworkPolicy examples, see the [NetworkPolicy getting started guide](/docs/getting-started-guides/network-policy/walkthrough). {% endcapture %} {% include templates/concept.md %}