[Unit]
Description=AutoSSH tunnel service, remote port $REMOTE_PORT
After=network-online.target
Wants=network-online.target
[Service]
Environment=AUTOSSH_GATETIME=0
Environment=REMOTE_USER=
Environment=REMOTE_HOST=
Environment=REMOTE_SSH_PORT=22
Environment=RPORT_LPORT=12345:localhost:22
Environment=SSH_KEY_PATH=
ExecStart=/usr/bin/autossh -M 0 -o "ServerAliveInterval 30" -o "ServerAliveCountMax 3" -N -R $RPORT_LPORT -l $REMOTE_USER -p $REMOTE_SSH_PORT -i $SSH_KEY_PATH $REMOTE_HOST
Restart=always
User=
[Install]
WantedBy=multi-user.target