diff --git a/src/rhcsa.md b/src/rhcsa.md
index 5687c80..3c72446 100644
--- a/src/rhcsa.md
+++ b/src/rhcsa.md
@@ -743,8 +743,22 @@ sudo dnf repolist # List all repositories
 ## Understand and Configure Firewalls
 
 ### firewall-cmd
+> Note: firewall-cmd is used to manage the firewall rules.
 ```bash
 sudo firewall-cmd --get-active-zones # Display the active zones
 sudo firewall-cmd --get-default-zone # Display the default zone
 sudo firewall-cmd --get-zones # Display the zones
-```
\ No newline at end of file
+
+sudo firewall-cmd --list-all # Display all the rules in the firewall
+
+sudo firewall-cmd --zone=public --add-service=http --permanent # Add the http service to the public zone
+sudo firewall-cmd --zone=public --add-port=80/tcp --permanent # Add the port 80/tcp to the public zone
+sudo firewall-cmd --zone=public --add-protocol=tcp --permanent # Add the tcp protocol to the public zone
+
+sudo firewall-cmd --reload # Reload the firewall
+```
+
+### port reference
+```bash
+sudo less /etc/services # Display the services
+```