diff --git a/modules/configuring-firewall.adoc b/modules/configuring-firewall.adoc
index babd548e9f..4ef8359a8b 100644
--- a/modules/configuring-firewall.adoc
+++ b/modules/configuring-firewall.adoc
@@ -75,23 +75,26 @@ Before you install {product-title}, you must configure your firewall to grant ac
 |URL | Function
 
 |`mirror.openshift.com`
-|Required to access mirrored installation content and images
+|Required to access mirrored installation content and images. This site is also a source of release image signatures, although the Cluster Version Operator needs only a single functioning source.
+
+|`storage.googleapis.com/openshift-release`
+|A source of release image signatures, although the Cluster Version Operator needs only a single functioning source.
 
 |`*.apps.<cluster_name>.<base_domain>`
-|Required to access the default cluster routes unless you set an ingress wildcard during installation
+|Required to access the default cluster routes unless you set an ingress wildcard during installation.
 
 |`quay-registry.s3.amazonaws.com`
-|Required to access Quay image content in AWS
+|Required to access Quay image content in AWS.
 
 |`api.openshift.com`
-|Required to check if updates are available for the cluster
+|Required to check if updates are available for the cluster.
 
 |`art-rhcos-ci.s3.amazonaws.com`
-|Required to download {op-system-first} images
+|Required to download {op-system-first} images.
 
 |`api.openshift.com`
-|Required for your cluster token
+|Required for your cluster token.
 
 |`cloud.redhat.com/openshift`
-|Required for your cluster token
+|Required for your cluster token.
 |===