How to Configure Multiple Mapping Port through One Port Forwarding Rule

There is a server inside of the network with use port 3389, 21, 9000 and needs to be accessed from Internet.
1. a UTT Business Router (hereinafter shorted as “the Router"), such as UTT router N518W, AC750W, AC750GW, AC1220GW, ER518, ER840G and ER4240G. Firmware Version: 3.0.0 or above
2. a PC/laptop connected to the Router wirelessly or through an Ethernet cable
1. Open a browser. Log into the Web UI of the UTT Business Router (default IP address, username: admin, password: admin).
2. Go to Network > NAT, click Add.
3. Input server IP at Internal Address, select protocol and enter Internal port as 3389, 21, 9000 (Click “+” button to add port forwarding rules.) and then save the configuration.
4. There are four ports listed in one NAT rule, port forwarding enabled automatically once the rule was created.
Note: Maximum 10 ports mapping can be configurated in one port forwarding rule.