方法一：
Connection to 192.168.2.100，192.168.2.101
找到/root/.ssh下，刪除所有文件，若無.ssh文件夾。相互ssh初始化後，會生成.ssh目錄。
[root@localhost ~]# ls /root/.ssh
known_hosts
[root@localhost ~]# cd /root/.ssh
[root@localhost .ssh]# rm -rf * #刪除所有文件
[root@localhost .ssh]# ssh-keygen
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
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:
cd:f0:ba:08:0b:31:a6:a7:4f:15:3a:11:24:f4:63:38 [email protected]
[root@localhost .ssh]#
[root@localhost .ssh]# ll
total 8
-rw------- 1 root root 1675 Jun 22 18:43 id_rsa
-rw-r--r-- 1 root root 408 Jun 22 18:43 id_rsa.pub #生成公鑰和私鑰
[root@localhost .ssh]# scp id_rsa.pub [email protected]:/root/.ssh/authorized_keys
The authenticity of host '192.168.2.101 (192.168.2.101)' can't be established.
RSA key fingerprint is 37:1a:c4:32:79:9d:0f:4d:85:94:4e:4b:59:39:19:ea.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '192.168.2.101' (RSA) to the list of known hosts.
[email protected]'s password:
id_rsa.pub 100% 408 0.4KB/s 00:00
#上傳公鑰到客戶端.ssh下
[root@localhost .ssh]# ssh 192.168.2.101
Last login: Sat Jun 21 02:21:49 2014 from 192.168.2.100
Welcome to Dengmin's lab! It's Sat Jun 21 02:23:57 CST 2014 #實現無密碼登陸，反之亦然