ppp0 to eth0 SSH tunnel routing

Question

I have Debian based ARM board on which I have Ethernet controller eth0 with static IP 192.168.1.10 and 3G usb modem connected to the internet (ppp0). Ethernet controller is connected directly to other device (seismic recorder) which also has static IP 192.168.1.100.

ARM board initiates SSH tunnel to the central server so I can access it even when 3G IP is not public nor static.

What I need to do is to be able to connect (via SSH tunnel initiated by ARM board) from server to port 5000 of seismic recorder. How should I do that?

Answer 1

I am not entirely sure I have understood what you're asking. If you want to connect from a server, through the ARM board to the seismic recorder, this should do what you want:

ssh -fN user@192.168.1.10 -L 5000:192.168.1.100:5000

The above command will connect to 192.168.1.10 and link your local port 5000 to the port 5000 of 192.168.1.100. Once you have run the command on your server, the seismic recorder will be connected to the server's port 5000.