in the host linux we need do this:
$:ssh-keygen -t dsa
answer all as default (Enter is ok),it will generate two files: id_dsa id_dsa.pub
2. cp id_dsa.pub to the server u want to login (u can use ftp or scp .etc)
3. login the server, then do
cp id_dsa.pub ~/.ssh
cat id_dsa.pub >>authorized_keys
after that. u can login the server from the host without passwd.