使用client的xiaoming用户基于密钥认证方式通过端口2000使用ssh登录server端的小明用户和xiaohei用户，server端的其他用户都不可被远程登录
服务端：hostname server
1.装包openssh，关闭防火墙和selinux
[root@server ~]# rpm -qa | grep openssh
openssh-server-8.0p1-4.el8_1.x86_64
openssh-clients-8.0p1-4.el8_1.x86_64
openssh-8.0p1-4.el8_1.x86_64
2.修改配置文件
[root@server ~]# vim /etc/ssh/sshd_config
添加端口号2000 port 2000
添加白名单 allowusers xiaoming xiaohei
3.重启服务
4.添加xiaoming xiaohei用户，并设置相应密码（之后在客户端测试）
客户端：client
1.装包openssh，关闭防火墙和selinux
[root@client ~]# rpm -qa | grep openssh
openssh-server-8.0p1-4.el8_1.x86_64
openssh-clients-8.0p1-4.el8_1.x86_64
openssh-8.0p1-4.el8_1.x86_64
2.测试xiaoming用户通过密码登录
[root@client ~]# ssh xiaoming@192.168.168.130 -p 2000
The authenticity of host ‘[192.168.168.130]:2000 ([192.168.168.130]:2000)’ can’t be established.
ECDSA key fingerprint is SHA256:ZMs9qjMq+bGHVvorhHgHt9w0QwTJaDZ3zozM0tIXbBk.
Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
Warning: Permanently added ‘[192.168.168.130]:2000’ (ECDSA) to the list of known hosts.
xiaoming@192.168.168.130’s password:
3.添加xiaoming用户，切换到xiaoming的身份（su - xiaoming）配置密钥的登录
[xiaoming@client ~]$ ssh-keygen -t rsa
4.将客户端xiaoming的家目录传到服务端xiaoming xiaohei 的家目录中
第一种
[xiaoming@client ~]$ ssh-copy-id xiaoming@192.168.168.130 -p 2000
Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
xiaoming@192.168.168.130’s password:
之后切换到服务端
[root@server ~]# cd /home/xiaoming/
[root@server xiaoming]# ls -a .ssh/
. … authorized_keys
随后客户端免密登录
[xiaoming@client ~]$ ssh xiaoming@192.168.168.130 -p 2000
第二种
[xiaoming@client ~]$ scp -P 2000 .ssh/id_rsa.pub xiaohei@192.168.168.130:/home/xiaohei/.ssh
xiaohei@192.168.168.130’s password:
id_rsa.pub 100% 569 78.1KB/s 00:00
服务端查看（.ssh）
[root@server xiaoming]# cd /home/xiaohei/
[root@server xiaohei]# ls -a
. … .bash_logout .bash_profile .bashrc .mozilla .ssh
[root@server xiaohei]# mv .ssh authorized.keys
[root@server xiaohei]# ll
总用量 4
-rw-r–r--. 1 xiaohei xiaohei 569 9月 30 22:06 authorized.keys
[root@server xiaohei]# mkdir .ssh
[root@server xiaohei]# chown xiaohei: .ssh/
[root@server xiaohei]# ll -a
总用量 16
drwx------. 4 xiaohei xiaohei 113 9月 30 22:10 .
drwxr-xr-x. 10 root root 121 9月 30 21:53 …
-rw-r–r--. 1 xiaohei xiaohei 569 9月 30 22:06 authorized.keys
-rw-r–r--. 1 xiaohei xiaohei 18 8月 30 2019 .bash_logout
-rw-r–r--. 1 xiaohei xiaohei 141 8月 30 2019 .bash_profile
-rw-r–r--. 1 xiaohei xiaohei 312 8月 30 2019 .bashrc
drwxr-xr-x. 4 xiaohei xiaohei 39 7月 25 11:56 .mozilla
drwxr-xr-x. 2 xiaohei xiaohei 6 9月 30 22:10 .ssh
[root@server xiaohei]# mv authorized.keys .ssh/
客户端使用xiaohei登录
[xiaoming@client ~]$ ssh xiaohei@192.168.168.130 -p 2000
