ssh以root用户登录ubuntu服务器

• 更改root密码

  一般情况安装Ubuntu时,不会提示root用户的相关信息,自然无法知道root用户的密码.Ubuntu的root用户的密码是随机的,即每一次开机,都有一个新的root密码.我们在以其他用户进入系统后,可以使用sudo passwd 命令修改密码,输入新的密码后,此时的密码就是root用户的密码.之后再输入su root 就用这个密码就可以了.

• 用ssh 以root用户登录服务器

  有了root用户的密码,还不能用ssh登录该服务器,因为ssh默认是阻止以root用户进行远程登录的.

  要使用root 用户登录,需要更改配置文件,做一下操作

  [email protected]:~
  $ ssh [email protected].168.122.xxx #以普通用户登录
  [email protected].168.122.xxx's password: 
  Welcome to Ubuntu 18.04.1 LTS (GNU/Linux 4.15.0-36-generic x86_64)
  
   * Documentation:  https://help.ubuntu.com
   * Management:     https://landscape.canonical.com
   * Support:        https://ubuntu.com/advantage
  
    System information as of Thu Oct 25 08:09:04 UTC 2018
  
    System load:  0.0               Processes:           93
    Usage of /:   7.6% of 97.93GB   Users logged in:     0
    Memory usage: 9%                IP address for ens3: 192.168.122.190
    Swap usage:   0%
  
   * Security certifications for Ubuntu!
     We now have FIPS, STIG, CC and a CIS Benchmark.
  
     - http://bit.ly/Security_Certification
  
   * Want to make a highly secure kiosk, smart display or touchscreen?
     Here's a step-by-step tutorial for a rainy weekend, or a startup.
  
     - https://bit.ly/secure-kiosk
  
  
   * Canonical Livepatch is available for installation.
     - Reduce system reboots and improve kernel security. Activate at:
       https://ubuntu.com/livepatch
  
  28 packages can be updated.
  0 updates are security updates.
  
  
  Last login: Thu Oct 25 08:00:28 2018 from 192.168.122.1
  [email protected]:~$ su root  #切换到root用户
  Password: 
  #修改配置文件
  [email protected]:/home/eric# vim /etc/ssh/sshd_config
  
  -----注释掉 PermitRootLogin without-password
  ------添加 PermitRootLogin yes
  
  #####重启服务
  [email protected]:/home/eric# /etc/init.d/ssh restart
  [ ok ] Restarting ssh (via systemctl): ssh.service.
  [email protected]:/home/eric# exit
  
  #退出后重新以root登录
  
  [email protected]:~
  $ ssh [email protected].168.122.xxx
  [email protected].168.122.xxx's password: 
  Welcome to Ubuntu 18.04.1 LTS (GNU/Linux 4.15.0-36-generic x86_64)
  
   * Documentation:  https://help.ubuntu.com
   * Management:     https://landscape.canonical.com
   * Support:        https://ubuntu.com/advantage
  
    System information as of Thu Oct 25 08:13:38 UTC 2018
  
    System load:  0.0               Processes:           95
    Usage of /:   7.6% of 97.93GB   Users logged in:     0
    Memory usage: 9%                IP address for ens3: 192.168.122.190
    Swap usage:   0%
  
   * Security certifications for Ubuntu!
     We now have FIPS, STIG, CC and a CIS Benchmark.
  
     - http://bit.ly/Security_Certification
  
   * Want to make a highly secure kiosk, smart display or touchscreen?
     Here's a step-by-step tutorial for a rainy weekend, or a startup.
  
     - https://bit.ly/secure-kiosk
  
  
   * Canonical Livepatch is available for installation.
     - Reduce system reboots and improve kernel security. Activate at:
       https://ubuntu.com/livepatch
  
  28 packages can be updated.
  0 updates are security updates.
  
  
  
  The programs included with the Ubuntu system are free software;
  the exact distribution terms for each program are described in the
  individual files in /usr/share/doc/*/copyright.
  
  Ubuntu comes with ABSOLUTELY NO WARRANTY, to the extent permitted by
  applicable law.
  
  #登录成功
  [email protected]:~#