测试环境

主机名：Server1，用户名：test

主机名：Server2，用户名：test

我们想从Server1 不需要密码直接ssh登录到Server2。

使用用户test登录到server1.

执行下面命令

[test@server1 ~]$ ssh-keygen -t rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/home/test/.ssh/id_rsa):
Created directory ‘/home/test/.ssh’.
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/test/.ssh/id_rsa.
Your public key has been saved in /home/test/.ssh/id_rsa.pub.
The key fingerprint is:
49:a4:1e:b8:df:13:36:fa:25:5a:d3:d2:f5:9e:77:98 test@server1
[test@server1 ~]$

将会生成两个文件 id_rsa 和 id_rsa.pub

[test@server1 ~]$ ls -lrt .ssh/
total 8
-rw-r–r– 1 test test  410 Nov 27 23:06 id_rsa.pub
-rw——- 1 test test 1671 Nov 27 23:06 id_rsa
[test@server1 ~]$

把id_rsa.pub这个文件传到服务器server2中

[test@server1 ]$ cd /home/test/.ssh
[test@server1 .ssh]$ ls -lrt
total 8
-rw-r–r– 1 test test  410 Nov 27 23:06 id_rsa.pub
-rw——- 1 test test 1671 Nov 27 23:06 id_rsa
[test@server1 .ssh]$
[test@server1 .ssh]$ scp id_rsa.pub test@server2:~

使用test登录到Server2

检查.ssh目录是否存在

[ test@server2 }$ ls -ld /home/test/.ssh

如果不存在，则创建一个

[ test@server2 }$ mkdir -p /home/test/.ssh

在.ssh中创建一个新文件authorized_keys

[test@server2 .ssh]$ cd /home/test/.ssh
[test@server2 .ssh]$ touch  authorized_keys
[test@server2 .ssh]$ ls
authorized_keys

将id_rsa.pub（从server1中上传的）的内容复制到 authorized_keys

[[email protected]]$ cd ~
[test@server2 ~]$
[test@server2 ~]$ cat id_rsa.pub >> /home/test/.ssh/authorized_keys

检查.ssh和authorized_keys的所有者和权限，应该像下面这样

[test@server2 ~]$ ls -ld .ssh/
drw-r-xr-x 2 test test 4096 Nov 27 22:56 .ssh/
[test@server2 ~]$
[test@server2 ~]$ ls -lrt .ssh/
total 4
-rw-r–r– 1 test test 412 Nov 27 22:55 authorized_keys
[test@server2 ~]$
[test@server2 ~]$

Server2切换到root用户

检查ssh配置文件

vi   /etc/ssh/sshd_config

RSAAuthentication   yes
PubkeyAuthentication  yes

重启或重新加载sshd服务

/etc/init.d/sshd reload
/etc/init.d/sshd restart

测试

现在我们就可以在Server1上通过test用户，不需密码登录到Server2中了

[test@server1 ~]$ ssh test@server2的ip