Is static IP needed if using VPN to connect to IoT devices?

Question

I have an IoT solution that I need to connect to from remote. I don't have access to open ports nor set static IPs on-site where the IoT devices will be hosted so I was looking for other solutions.

An Idea is to use a VPN-box where I connect the devices to, and then connect the VPN-box (router?) to the on-site ethernet.

Would I then be able to connect to the devices from a raspberry pi (stored off-site) and would be able to access them with internal IPs since it is on the same VPN network?

In theory this sounds like a plausible solution – but I am not sure if I am missing something. So I am looking for an answer if this is even possible before purchasing VPN routers and licenses.

Would it work? Is there an even better solution for this?

The IoT devices are two I/O remotes (Moxa) which I am connecting to via python using pymodbus.

Answer 1

Yes, that should work. You will need a static way to address your VPN server (no need to pay license fee, just use OpenVPN), but this could be a AWS instance with the DNS entry.

But it sounds like you don't control the network that this will all be connected to. You need to talk to the owners of this network and explain what you are doing as you are opening up a way to remotely access their network (the VPN box needs access both to the sensors and the local network) if the external end of the VPN should become compromised. They may want to place your VPN device in a DMZ so it has no access to the rest of the internal network.

This type of network setup has been used to compromise large organisations in the past. E.g. the Casino fish tank monitoring software and A large supermarket that had remote monitoring of it's fridges.