How To:Set up transport encryption with SSH

Backup process amdump

• You must create an ssh key for the Amanda server, and make sure you just hit enter when asked for a key passphrase. In this example, the key is put in the id_rsa_amdump file (Run as backup user - amandabackup):

 $ ssh-keygen -t rsa -C "SSH Key for Amanda Backups"
 Enter file in which to save the key (/home/amandabackup/.ssh/id_rsa)? /home/amandabackup/.ssh/id_rsa_amdump

• You must set the ssh_keys option in all DLE for that host:

 ssh_keys "/home/amandabackup/.ssh/id_rsa_amdump"

• You mush append the /home/amandabackup/.ssh/id_rsa_amdump.pub file to the .ssh/authorized_keys (if unsure, check /etc/ssh/sshd_config for what your authorized_keys file is set to) file of all Amanda clients.

• For security reasons, you must prepend the line with the following:

 from="<Amanda_server_fqdn_name>",no-port-forwarding,no-X11-forwarding,
 no-agent-forwarding,command="<absolute path to amandad> -auth=ssh amdump"

This will limit that key to connect only from Amanda server and only be able to execute amandad.

• If your server username and client username are different, you must add the client_username option in dumptype definition for all DLEs in the client:

 client_username "client_backup_username"

• If your server amandad path and client amandad path are different, you must set the amandad_path option in all DLE for that hosts:

 amandad_path "client/amandad/path"

• Use the dumptype similar to the following:

define dumptype nocomp-ssh {
  root-tar
  comment "ssh authorization and dumped with tar"
  auth "ssh"
  ssh_keys "/var/lib/amanda/.ssh/id_rsa_amdump"
  compress none
}

• Make sure Amanda Client in the known_hosts file by doing:

$ ssh client1.zmanda.com
The authenticity of host 'client1.zmanda.com (192.168.10.1)' can't be established.
RSA key fingerprint is 26:4e:df:a2:be:c8:cb:20:1c:68:8b:cc:c0:3b:8e:9d.
Are you sure you want to continue connecting (yes/no)?yes

Recovery process amrecover

• Create a ssh key for root on all clients that can use amrecover. In this example, the key is put in the /root/.ssh/id_rsa_amrecover file:

Log in as root:

 # ssh-keygen -t rsa
 Enter file in which to save the key (/root/.ssh/id_rsa)? /root/.ssh/id_rsa_amrecover

• You must set the ssh_keys option in the /etc/amanda/amanda_client.conf file

 ssh_keys "/root/.ssh/id_rsa_amrecover"

• You mush append all client /home/root/.ssh/id_rsa_amrecover.pub file to the /home/amandabackup/.ssh/authorized_keys of the server.

• For security reasons, you must prefix all lines with the following:

from="aclient_fqdn_name",no-port-forwarding,no-X11-forwarding,
 no-agent-forwarding,command="/path/to/amandad -auth=ssh amindexd amidxtaped"

This will limit every client key to connect from the client and only be able to execute amandad.