Remote access via ssh without Password

On the Client, at the /root/.ssh/, run the following command to build keys:

ssh-keygen -t rsa

that builds two files:

id_rsa.pub and id_rsa

Copy id_rsa.pub to Remote Computer:

scp id_rsa.pub root@ip.for.remote.computer:/root/.ssh/

Then execute this command on Remote:

cat id_rsa.pub >> authorized_keys

and:

chmod 644 authorized_keys