SSH key- passwordless login

On the source server do the following

ssh-keygen -t dsa -f filename

It will prompt for a passphrace, it is desirable to leave it empty.
Two files will be created

filename
filename.pub

copy the filename.pub file to the destination server to the location /root/.ssh add the public key entry into authorized_keys as follows

cat filename.pub >> authorized_keys

/etc/init.d/sshd restart