diff --git a/content/en/docs/04/_index.en.md b/content/en/docs/04/_index.en.md
index d5a7e5bb..63d30ca6 100644
--- a/content/en/docs/04/_index.en.md
+++ b/content/en/docs/04/_index.en.md
@@ -62,6 +62,11 @@ Check `httpd.service` on group `web`:
 ```bash
  ansible -i hosts web -b -a "systemctl status httpd"
 ```
+
+{{% alert title="Hint" color="info" %}}
+The ports for ssh, dhcp and cockpit are opened by default in the firewalld. It is best, especially for documentation, to open the ports explicitly in a basic settings file.
+{{% /alert %}}
+
 {{% /details %}}
 
 ### Task 2