Port forwarding on the Robustel can be configured from the router web interface 

Once in the screen click on the + icon 

Complete the required source and destination information 

Please note – for the port information (Internet and Local) you will need to enter port:port 

In the example above, the ports are 25 and 981 so when adding the rule, the ports were added as 25:25 and 981:981 

Click Submit (bottom right)