運維學習之openssh-server命令運用及控制
openssh-server
1.openssh-server
功能：讓遠程主機可以通過網絡訪問sshd服務，開始一個安全shell
2.客戶端連接方式
ssh [email protected]
[[email protected] ~]# ssh [email protected]
The authenticity of host ‘172.25.0.11 (172.25.0.11)‘ can‘t be established.
ECDSA key fingerprint is eb:24:0e:07:96:26:b1:04:c2:37:0c:78:2d:bc:b0:08.
Are you sure you want to continue connecting (yes/no)? yes ##連接陌生主機時需要建立認證關系
Warning: Permanently added ‘172.25.0.11‘ (ECDSA) to the list of known hosts.
[email protected] password: ##遠程用戶密碼
Last login: Mon Oct 3 03:13:47 2016
[[email protected] ~]# ##登陸成功
ssh [email protected]
ssh [email protected] command ##直接在遠程主機運行某條命令
3.sshkey加密
1.生成公鑰私鑰
[[email protected] ~]# ssh-keygen
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa):[enter] ##加密字符保存文件（建議用默認）
Created directory ‘/root/.ssh‘.
Enter passphrase (empty for no passphrase): [enter] ##密鑰密碼，必須>4個字符
Enter same passphrase again: [enter] ##確認密碼
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:
ab:3c:73:2e:c8:0b:75:c8:39:3a:46:a2:22:34:84:81 [email protected]
The key‘s randomart image is:
+--[ RSA 2048]----+
|o |
|E. |
|.. |
|. . o |
|.o. * . S |
|oo.o o . |
|+ =. . . |
|o. oo.+.. |
| ..o*. |
+-----------------+
[[email protected] ~]# ls /root/.ssh/
id_rsa id_rsa.pub
id_rsa ##私鑰，就是鑰匙
id_rsa.pub ##公鑰，就是鎖
2.添加key認證方式
[[email protected] ~]# ssh-copy-id -i /root/.ssh/id_rsa.pub [email protected]
ssh-copy-id ##添加key認證方式的工具
-i ##指定加密key文件
/root/.ssh/id_rsa.pub ##加密key
root ##加密用戶為root
172.25.0.11 ##被加密主機ip
3.分發鑰匙給client主機
[[email protected] ~]# scp /root/.ssh/id_rsa [email protected]:/root/.ssh/
4.測試
[[email protected] ~]# ssh [email protected] ##通過id_rsa直接連接不需要輸入用戶密碼
Last login: Mon Oct 3 03:58:10 2016 from 172.25.0.250
[[email protected] ~]#
4.提升openssh的安全級別
1.openssh-server配置文件
/etc/ssh/sshd_config
78 PasswordAuthentication yes|no ##是否開啟用戶密碼認證，yes為支持no為關閉
48 PermitRootLogin yes|no ##是否允許超級用戶登陸
49 AllowUsers student westos ##用戶白名單，只有在名單中出現的用戶可以使用sshd建立shell
50 DenyUsers westos ##用戶黑名單
2.控制ssh客戶端訪問
vim /etc/hosts.deny
sshd:ALL ##拒絕所有人鏈接sshd服務
vim /etc/hosts.allow
sshd:172.25.254.250 ##允許250主機鏈接sshd
sshd:172.25.254.250， 172.25.254.180 ##允許250和180鏈接
sshd:ALL EXCEPT 172.25.254.200 ##只不允許200鏈接sshd
3.ssh登陸提示修改該
vim /etc/motd ##顯示登陸後字符
hello world ##在登陸後就會顯示這個字符
運維學習之openssh-server命令運用及控制