using arduino mkr gsm 1400 to access internal FTP via a VPN?

Hi,
We have a number of arduino mkr gsm 1400 boards in remote/isolated locations that record data and upload that data over a 3G link to a public FTP server and these work very well, however is it possible to use the same board to make use of APN sims that have static IP addresses and then access an internal/non-public FTP server via a VPN? I assumed that it wouldnt be possible but i also do not have much knowledge of VPNs either.

Any help is much appreciated.

Cheers.

VPN usually requires a client software (a VPN client that runs on the user computer). If there's a VPN library that can be incorporated into the Arduino, then you probably can re-compile code with VPN built-in support. I've never seen one