I have a question about the configuration of one tunnel SSh - Actually, I have found a working solution, but is not normal that it works! I don't understand and it's really weird. I'm feeling to make something magical and I'm a bit afraid.
Machine on Ubuntu 18.04 and Debian (raspberrypi)
When I open a tunnel from a remote computer (id: robert) "inaccessible" (Ubuntu behind a gsm connection) to the raspberry pi, himself behind a fixed router, I use this command:
ssh -R 22222:localhost:22 firstname.lastname@example.org
ssh -NR 22222:localhost:22 email@example.com
In return, I have two errors, but the tunnel seems to work properly because I can connect and control the remote computer from the raspberry machine with:
ssh -p 22222 firstname.lastname@example.org
The error: Tunnel device open failed. Could not request tunnel forwarding.
That's not all !! This is working even with the following parameters at OFF or commented on the two machines (sshd_config): AllowTCPForwarding off, GatewayPorts off, PermitTunnel off
Someone may explain that? :) Thanks
I don't have autossh installed. The same with another port.