Question

For easy integration, I want to connect an RUT240 router or TRB140 gateway to my customers existing LAN (which has a router + internet access), to be able to communicate over 4G with a specific device connected to customers LAN. The RUT240 or TRB140 should be configured to establish a VPN connection to my server, and all communication goes from the server through the VPN tunnel to the device on customers LAN. My customers does asometimes also need to be able to connect to the device web ui on the LAN.

Is this possible to setup, and is RUT240 better suited than TRB140 for this?

Answer 1

This is easily done with Zerotier or OpenVPN. Just follow the guides in the wiki here to set it up.
Zerotier is probably easiest as you can quickly install that on laptops that need access without using a server.

It is probably best to connect the RUT240 WAN port to the customers LAN switch.
If you can get a static IP from them and the device also has static IP this will work even if their router is offline.