file per
domain, then the destination must be a directory which already exists. <p>

If backing up to an SSH or FTP server on a non-standard port, you can enter it
in the server field separated from the hostname with a colon, like 
<tt>backupserver.yourdomain.com:2222</tt> . <p>

If backing up to an SSH server that only supports certificate-based
authentication, the password field is optional. However, the <tt>root</tt>
user on the system must have their SSH public key in the destination user's
<tt>authoriz