建立SSH的信任关系

# ssh-keygen  -t rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa): 
Enter passphrase (empty for no passphrase):            <-- 直接输入回车
Enter same passphrase again:                           <-- 直接输入回车
Your identification has been saved in /root/.ssh/id_rsa.
Your public key has been saved in /root/.ssh/id_rsa.pub.
The key fingerprint is:
49:9c:8a:8f:bc:19:5e:8c:c0:10:d3:15:60:a3:32:1c root@Server

# scp -p /root/.ssh/id_rsa.pub root@121.40.125.251:/root/.ssh/
root@192.168.0.20‘s password:          <-- 输入机器Client的root用户密码
id_rsa.pub           100% |**************************|   218       00:00

# mv /root/.ssh/id_rsa.pub /root/.ssh/authorized_keys   <--  或者 
cat id_rsa.pub >authorized_keys

# scp -i  /root/ .ssh/id_rsa text  root@192.168.0.20:/root
text                 100% |**************************|    19       00:00