Hi Redfive, thanks for your reply.
We have our 4G modem working (internet) but we also want to access our office from outside. If we want to connect to our servers we need forwarding IP or VPN. The public IP we get from our ISP is dynamic (92.xxx.xxx.xxx), the 4G modem gets a local IP starting with 100.xxx and remote IP is 10.64.64.64 I think the problem is caused by the APN we have to use, but I am not sure.
I want to know if its possible to change the modem remote/local IP settings?