ES450 RDP access


I have a laptop1 connected to an ES450 GSM Modem using a Vodafone Sim.
I have another laptop2 in the office connected to internet

I can RDP from laptop1 to laptop2
I can NOT RDP from laptop2 to laptop1 confirms Public IP address of GSM Modem is 213.x.x.x
Active WAN IP address of ES450 Manager shows 10.142.x.x

Which IP is the actual Public IP ?

I’ve tried RDP’ing to both IP’s but no luck.

I understand the Sim should have a static IP, is this my main problem?
I need a Static Sim from ISP and what else does sim need to allow ?