1. New rule in "Firewall -> Access Rules"
2. Click "Server Mangement" to define new services ports. This router does not allow you to define udp ports 443-65534 in a service because UDP 1701 already exists. So we need to define two services.
New service on udp ports 443-1700
New another service on udp ports 1702-65534
3. Add two deny rules
Please notice: