Backup files with hardlinks from DMZ

From wiki.network-crawler.de

Create a revers ssh tunnel (on backup system):

ssh -N -C -p 22 -R 2222:127.0.0.1:22 <server with the files>

Add a exception for ssh port on the system with the files to be backuped (/etc/ssh/ssh_config):

Host <backup system>
	Hostname localhost
	Port 2222
	HostKeyAlias ssh_tunnel
	User root

then start the backup:

rsync -aHzvv /home/ftpuser/ <backup system>:/home/ftpuser/