firewall-cmd: clarify runtime/permanent configuration and add commands (#13771)

pages/linux/firewall-cmd.md

@@ -1,15 +1,12 @@
 # firewall-cmd
 
 > The firewalld command-line client.
+> View and adapt the runtime or permanent firewall configuration state.
 > More information: <https://firewalld.org/documentation/man-pages/firewall-cmd>.
 
-- View the available firewall zones:
+- View all available firewall zones and rules in their runtime configuration state:
 
-`firewall-cmd --get-active-zones`
+`firewall-cmd --list-all-zones`
-
-- View the rules which are currently applied:
-
-`firewall-cmd --list-all`
 
 - Permanently move the interface into the block zone, effectively blocking all communication:
 
@@ -23,10 +20,18 @@
 
 `firewall-cmd --permanent --zone={{public}} --remove-service={{http}}`
 
-- Permanently open two arbitrary ports in the specified zone:
+- Permanently forward a port for incoming packets in the specified zone (like port 443 to 8443 when entering the `public` zone):
 
-`firewall-cmd --permanent --zone={{public}} --add-port={{25565/tcp}} --add-port={{19132/udp}}`
+`firewall-cmd --permanent --zone={{public}} --add-rich-rule='rule family="{{ipv4|ipv6}}" forward-port port="{{443}}" protocol="{{udp|tcp}}" to-port="{{8443}}"'`
 
-- Reload firewalld to force rule changes to take effect:
+- Reload firewalld to lose any runtime changes and force the permanent configuration to take effect immediately:
 
 `firewall-cmd --reload`
+
+- Save the runtime configuration state to the permanent configuration:
+
+`firewall-cmd --runtime-to-permanent`
+
+- Enable panic mode in case of Emergency. All traffic is dropped, any active connection will be terminated:
+
+`firewall-cmd --panic-on`