Hi, I have a series of small embedded devices I want to backup over ssh to a central server. Most are not reachable from the server, so the clients need to talk / initiate connections to the server. As the server is just meant to get backup files, I want to provide the bare min access to the client. On the client, I was thinking of something like the client doing USER=clientsite HOST=mybackup.server.com /usr/bin/tar -cpzf - /cfg | ssh $USER@$HOST backup.sh and the authorized_keys file being from="192.168.22.254",no-port-forwarding,no-X11-forwarding,no-pty,command="./backup.sh" ssh-rsa AAAAB3NzaC1y.... and backup.sh #!/bin/sh set -euf d=`date "+%d"` cat - > ~clientsite/backup-$d.tgz If the client private key got into the wrong hands, apart from potentially deleting backupfiles from that day, is there any other "bad things" they could do ? Could they somehow abuse STDIN to create new files ? ---Mike -- ------------------- Mike Tancsa, tel +1 519 651 3400 Sentex Communications, mike at sentex.net Providing Internet services since 1994 www.sentex.net Cambridge, Ontario Canada http://www.tancsa.com/