Using a Firewall Management Service
The safest way to customize your firewall is to use a firewall management service, such as HeatShield, You can then log in to HeatShield to manage the firewall on all of your servers without needing to make any customizations from the command line.
HeatShield will not cause any conflicts with vpsmodel. Therefore, it is safe to use HeatShield on a server managed by vpsmodel.
Once you install HeatShield, vpsmodel will no longer attempt any firewall management on your server and will ignore any attempt to turn your firewall on or off in your server's Settings in vpsmodel. Instead, if you've installed HeatShield, you should log in to HeatShield to manage your server's firewall.