Secure Tunnel Service

Here's a simple ssh based way setup a remote tunnel to a server.

root@raspberrypi:~# ssh-keygen -t ed25519

cat >/etc/systemd/system/secure-tunnel@.service <<'EOF' 
[Unit]
Description=Setup a secure tunnel to %I
After=network.target

[Service]
ExecStart=/usr/bin/ssh -NT -F /etc/default/secure-tunnel.config  %i

# Restart every >2 seconds to avoid StartLimitInterval failure
RestartSec=5
Restart=always

[Install]
WantedBy=multi-user.target
EOF

cat > /etc/default/secure-tunnel.config <<'EOF' 
Host keekles
        HostName keekles.org
        User 
        IdentityFile  /root/.ssh/id_ed25519
        RemoteForward 34500 127.0.0.1:22
        ServerAliveInterval 60
        ExitOnForwardFailure yes
EOF

systemctl enable secure-tunnel@keekles.service
systemctl status secure-tunnel@keekles.service

Connecting to the remote device via the server

$ ssh bryan@127.0.0.1 -p 34500 -J keekles