diff --git a/content/rancher/v2.x/en/cluster-admin/tools/monitoring/prometheus/_index.md b/content/rancher/v2.x/en/cluster-admin/tools/monitoring/prometheus/_index.md
index b4fac99a95b..0f667bcd1a6 100644
--- a/content/rancher/v2.x/en/cluster-admin/tools/monitoring/prometheus/_index.md
+++ b/content/rancher/v2.x/en/cluster-admin/tools/monitoring/prometheus/_index.md
@@ -28,6 +28,8 @@ The [node exporter](https://github.com/prometheus/node_exporter/blob/master/READ
 
 When configuring Prometheus and enabling the node exporter, enter a host port in the **Node Exporter Host Port** that will not produce port conflicts with existing applications. The host port chosen must be open to allow internal traffic between Prometheus and the Node Exporter.
 
+>**Warning:** In order for Prometheus to collect the metrics of the node exporter, after enabling cluster monitoring, you must open the **Node Exporter Host Port** in the host firewall rules to allow intranet access. By default, `9796` is used as that host port.
+
 ## Persistent Storage
 
 >**Prerequisite:** Configure one or more [storage class]({{< baseurl >}}/rancher/v2.x/en/cluster-admin/volumes-and-storage/#adding-storage-classes) to use as [persistent storage]({{< baseurl >}}/rancher/v2.x/en/cluster-admin/volumes-and-storage/) for your Prometheus or Grafana pod.