FIP-PVN has following applications:
1st) Your network is connected via Internet connection withput official IP address. Therefore you do not have any IPv4 or IPv6 connection, which directly features your network (mobile communications).
2nd) You do not have access to the router in network to establish port release or forwarding, or you do not want to change your router in any way, because it is maintainedby the provider.
3rd) Your terminal device needs IPv4 address to communicate in both directions. (Email / some NAS with cloud connection).
Every named application can be realized with FIP-VPN. These 3 variations set apart from each other slightly.With every variation VPN can be established from the inside to the outside to avoid changes of current devices. VPN can only be established via random Internet connection.
The applications are very multiple. Combined with FIP-Box / UMTS-card / SMS you can also create a simple access fpr maintenance with On/Off-button (via SMS), which works completely independent.