#apt-get install autossh
#ssh-keygen…
# cat /etc/rc.local
…
/usr/bin/autossh -M {monitoring port} -N -f -o «PubkeyAuthentication=yes» -o «PasswordAuthentication=no» -o «ServerAliveInterval 30» -o «ServerAliveCountMax 3» -i /path/to/ssh_key -R 12345:localhost:{ssh port} {user}@{remote server} -p {remote ssh port}
exit 0