I have a device running Linux (Debian) installed at a remote location with internet access.
I can't modify the remote location's firewall, and the public IP address is dynamic.
How can I access this machine via SSH from outside the machine's LAN, without modifying the firewall to port-forward port 22 to the machine?
NOTE: I have a web-facing cloud server available with static IP address, and the remote device contacts this server every 5 seconds to retrieve configuration data. I could push a command to the device if necessary to initiate some sort of reverse SSH tunnel, but I'm not sure how to then utilize that tunnel from the server and/or my local desktop.
Having the ability to SFTP files to the device from either the cloud server or my local desktop would be a huge added bonus.
Thanks for any advice or suggestions on how to accomplish this!