ssh without password

Hello ! I wish to make a backup script for copy some files from one server to other via scp ... Supouse I have 2 servers named server1 and server2 . -server1: ssh-keygen -t rsa I put empty password scp id_rsa.pub root@server2:~root/.ssh/know_hosts2 -server2: when I wish to run : ssh server1 server1 ask me for password ... Where I can find a good explanation for this stuff ? Thank You ! -- Powered by SuSE Linux 7.3 Professional Kernel Version: 2.4.16-4GB Current Linux Uptime: 9 days 3 hours 23 minutes 5 users Load Average: 0.12,0.04,0.01