Linux服务器如何禁用密码登录，使用秘钥文件登录增加服务器安全性？

生成秘钥公钥

$  ssh-keygen       //生成秘钥
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:
The key's randomart image is:
+---[RSA 2048]----+
|      .o=B@*.    |
|   . = =o*.*.    |
|. . + @ + o o    |
|oo o * +         |
|o +.. + S        |
|.oo.   .         |
| =.              |
|..=oE            |
| *+ o.           |
+----[SHA256]-----+



$ cat /root/.ssh/id_rsa.pub >> /root/.ssh/authorized_keys  //把公钥放进授权文件中去

$ cd /root/.ssh

$  chmod 600 authorized_keys

$  chmod 700 ~/.ssh

$  vim /etc/ssh/sshd_config

RSAAuthentication yes
PubkeyAuthentication yes
PermitRootLogin yes   //另外，请留意 root 用户能否通过 SSH 登录，默认为yes：
 
当我们完成全部设置并以密钥方式登录成功后，可以禁用密码登录。这里我们先不禁用，先允许密码登陆
PasswordAuthentication yes
    
$ service sshd restart //重启服务

客户端使用秘钥登录

1. /root/.ssh/id_rsa 到Windwos桌面 更改为.pem文件 
2.使用SecurtCRT SSH远程连接工具进行登录 
3.登录成功后 请把/etc/ssh/sshd_config 文件中的PasswordAuthentication改为No 禁止密码进行远程登录 防止服务器被恶意SSH暴力破解攻击

服务器被攻击如图