Open Hosting now offers network firewalls. As of today, you can buy a network firewall for your server for $2/month.
The firewall is very simple. Click “enabled” and specify the UDP and TCP ports you want left open in a space-separated list. For instance:
Once you’ve enabled, the red firewall icon will appear besides your server.
The firewall is platform-level, operating independently of your server it blocks traffic before it hits your server.