TCP socket server with cellular framework

Hello,

I'am trying to create an tcp server using the cellular (IOT-CLOUD2 kit). Unfortunately the socket is not reachable from outside.

What i did:

1 - I have created a tcp client connection to my server to get the public IP of my cellular.

2 - Then i created an socket server ( port 12) in the MCU.

3 - Using the IP identified in step 1 i tried to establish a connection to the tcp server from my laptop. 

N.B: i noticed in step 1 that the ip address shown by the NX_IP instance (using nx_ip_address_get) is different from the IP identified by my socket server on my laptop. Maybe a NAT between the GSM and my laptop ?

Have you some advice about that ?