I am using Airtel 4G dongle(Huawei E3372 Firmware 21.x.x version) with TL-MR3420 and able to connect to Internet. However, port forwarding option is not working. 

I did enable port forward option using the below steps 

1) Setup a fixed ip address to CCTV camera (192.168.1.60) which i need to accesss it from internet.

2) Setup port forwarding rules as below 

• Virtual servers -> Service Type : HTTP , External Port : 8001,Internal IP : 192.168.1.60, Internal Port : 80,  Protocol : TCP & UDP (All)

When i tried to analyze this, it looks to me that 4G Dongle is getting external facing IP (223.186.191.107) and it is assigning 100.78.112.179 address to router (WAN Interface Name:   ppp_USB_3G, Default Gateway : 10.64.64.65) . 

Please help me to setup the dongle / Router correctly so that Dongle works as modem only and Router gets external facign IP address.