远程密钥登录

当需要同时管理上前台服务器的时候，如果挨个输入密码登录服务器就会很麻烦。我们可以用linux自带的ssh工具，设置密钥免密码登录。
实验环境：机器A:192.168.241.128

机器B:192.168.241.130

A机器上的操作

[root@1111 ~]# ssh-keygen ###生成密钥对
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa):
Created directory '/root/.ssh'.
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:
dc:17:23:8c:62:a4:37:ac:24:b4:8f:e6:3c:6a:ee:c5 root@1111
The key's randomart image is:
+--[ RSA 2048]----+
| . . |
| . . + o |
| o o * . o o |
| = + + . . o |
| o o S . . |
| +. . |
| +E |
| o.. |
|=o |
+-----------------+
[root@1111 ~]# cat /root/.ssh/id_rsa.pub #在相应目录下找到公钥，并复制其内容
ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEAsrEF5lUYe7u1i5v7ObcXDhqf3kPU9gJBF32xj/npllye99L S6k6NA/+lbjtKWZtR5sxXD2PfYE0z8t4DZ04fjDqVh6lMNWSmTWVP7DYmRHzqySUfDcH8NStVCHVt7J4ntu 7bfV4ixswdMTt+5nRgS71ILHJ46n+EPfjKzrHmXxed4a4FLRh7uqD+YGQdD7+wiZvAQTz2PogoucGNgaDSZ Ve44UC7SM6W0L2WgcZnP5XysUua33+dcqt1h+ZKwurR3RuYc0ptyjIP/leckoJ0A/YWgig86vzWLh4LbBfX KF7gtwqFjUb+8iyqDr9ARmBn2VSxIyHAAASZ45SzZxwNNQ== root@1111

B机器上的操作

[root@333 ~]# mkdir /root/.ssh
[root@333 ~]# vim /root/.ssh/authorized_keys 在该文件中粘贴刚刚复制的公钥内容
[root@333 ~]# chmod 700 /root/.ssh
[root@333 ~]# chmod 600 /root/.ssh/authorized_keys
[root@333 ~]# iptables -F
[root@333 ~]# service iptables save
iptables：将防火墙规则保存到 /etc/sysconfig/iptables： [确定]

先暂时关闭selinux：
[root@333 ~]# setenforce 0
再永久性关闭：

[root@333 ~]# vim /etc/selinux/config
将SELINUX=enforcing改为
SELINUX=disabled
保存退出。
进行以上操作后，再回到A机器上，测试是否成功

[root@1111 ~]# ssh 192.168.241.130
The authenticity of host '192.168.241.130 (192.168.241.130)' can't be established.
RSA key fingerprint is c2:09:a3:28:ec:61:cf:25:e9:9b:23:93:cb:4c:47:3f.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '192.168.241.130' (RSA) to the list of known hosts.
Last login: Sun Sep 18 19:04:08 2016 from 192.168.241.128
[root@333 ~]# logout
Connection to 192.168.241.130 closed.
[root@1111 ~]# ssh 192.168.241.130
Last login: Sun Sep 18 19:11:35 2016 from 192.168.241.128
成功通过密钥免密码登录