一、知识点
TCP Wrappers服务的防火墙策略由两个控制列表文件（/etc/hosts.allow和/etc/hosts.deny）所控制，用户可以编辑允许控制列表文件来放行对服务的请求流量，也可以编辑拒绝控制列表文件来阻止对服务的请求流量。
(1)控制列表文件修改后会立即生效，
(2)系统将会先检查允许控制列表文件（/etc/hosts.allow），如果匹配到相应的允许策略则放行流量；
(3)如果没有匹配，则去进一步匹配拒绝控制列表文件（/etc/hosts.deny），若找到匹配项则拒绝该流量。
(4)如果这两个文件全都没有匹配到，则默认放行流量。

  • Linux一切都是文件
  • 配置一个服务就是修改一个文件的配置文件
  • 要想是配置生效需要重启改服务
  • 需要将服务加入服务中保证重启后依然能提供服务
  1. 远程控制服务：ssh
  2. 基于口令的验证—用账户和密码来验证登录；
  3. 基于密钥的验证—需要在本地生成密钥对，然后把密钥对中的公钥上传至服务器，并与服务器中的公钥进行比较；该方式相较来说更安全。

[root@linuxprobe ~]# ssh 192.168.10.10
The authenticity of host '192.168.10.10 (192.168.10.10)' can't be established.
ECDSA key fingerprint is 4f:a7:91:9e:8d:6f:b9:48:02:32:61:95:48:ed:1e:3f.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '192.168.10.10' (ECDSA) to the list of known hosts.
[email protected]'s password:此处输入远程主机root管理员的密码
Last login: Wed Apr 15 15:54:21 2017 from 192.168.10.10
[root@linuxprobe ~]#
[root@linuxprobe ~]# exit
logout
Connection to 192.168.10.10 closed.


3. 秘钥生成

[root@linuxprobe ~]# ssh-keygen
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa):按回车键或设置密钥的存储路径
Created directory '/root/.ssh'.
Enter passphrase (empty for no passphrase):直接按回车键或设置密钥的密码

Enter same passphrase again:再次按回车键或设置密钥的密码
Your identification has been saved in /root/.ssh/id_rsa.
Your public key has been saved in /root/.ssh/id_rsa.pub.
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:
40:32:48:18:e4:ac:c0:c3:c1:ba:7c:6c:3a:a8:b5:22 [email protected]
The key's randomart image is:
+--[ RSA 2048]----+
|+*..o .          |
|*.o  +           |
|o*    .          |
|+ .    .         |
|o..     S        |
|.. +             |
|. =              |
|E+ .             |
|+.o              |

+-----------------+



一、照片
![](https://s1.51cto.com/images/blog/202003/10/f1821e6d0dfc909c09538be9abac326e.png?x-oss-process=image/watermark,size_16,text_QDUxQ1RP5Y2a5a6i,color_FFFFFF,t_100,g_se,x_10,y_10,shadow_90,type_ZmFuZ3poZW5naGVpdGk=)

![](https://s1.51cto.com/images/blog/202003/10/1267d95fa0fe67a28d227b53bac2ab48.jpg?x-oss-process=image/watermark,size_16,text_QDUxQ1RP5Y2a5a6i,color_FFFFFF,t_100,g_se,x_10,y_10,shadow_90,type_ZmFuZ3poZW5naGVpdGk=)