My RAK7258 gateway is the LTE version because there is no Ethernet nor WiFi Internet access near.
The problem is that my 4g provider assigns a private IP address (10.x.x.x), so I cannot remotely access the gateway from Internet.
It would be nice to include zerotier or similar in the RAK7258 openwrt firmware.
Indeed, one cannot make inbound connections to most mobile data network clients, at least not without special arrangements with the provider.
If you have an SSH jumphost or bastion available, it’s possible to use even openwrt’s stock “dropbear” ssh client to make an outbound connection creating a reverse tunnel back. The command line options are a little different than other SSH clients, and you’ll want to spend some time learning about procd scripting, but it’s do-able.
It would be nice if it worked out of the box, ideally in a way where you could select your own relay server and not just be tied to a provided one.