[系统运维]20.04.1-Ubuntu刚刚装完后的操作

一、修改root密码

初始安装的系统root密码随机，进入系统后需要使用普通用户重置root密码

user@user-virtual-machine:~$ sudo passwd     #使用root权限修改root密码
[sudo] password for user:       #输入user密码
New password:     #输入root得新密码
Retype new password:      #再次输入root新密码
passwd: password updated successfully
user@user-virtual-machine:~$ su root      #切换root用户
Password:      #输入root密码
root@user-virtual-machine:/home/user#      #已切换到root用户

二、开启ssh

安装过程

root@user-virtual-machine:~/Desktop# apt-get -y install openssh-server    #安装ssh服务

root@user-virtual-machine:~/Desktop# systemctl start ssh     #开启ssh服务

root@user-virtual-machine:~/Desktop# ps -ef |grep ssh    #查看ssh状态
root       11073       1  0 23:09 ?        00:00:00 sshd: /usr/sbin/sshd -D [listener] 0 of 10-100 startups
root       12409   10616  0 23:10 pts/0    00:00:00 grep --color=auto ssh

root@user-virtual-machine:~# apt-get install -y net-tools
root@user-virtual-machine:~# netstat -lntp |grep :22
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN      3007/sshd: /usr/sbi
tcp6       0      0 :::22

root@user-virtual-machine:~/Desktop# ip a     #查看IP地址
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 00:0c:29:89:a7:46 brd ff:ff:ff:ff:ff:ff
    altname enp2s1
    inet 192.168.163.155/24 brd 192.168.163.255 scope global dynamic noprefixroute ens33
       valid_lft 1607sec preferred_lft 1607sec
    inet6 fe80::d41a:57c1:e4e6:5172/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever

为了方便使用netstat指令查看端口

三、ssh服务开启和关闭的指令

#开启ssh服务
root@user-virtual-machine:~/Desktop# systemctl start ssh
或root@user-virtual-machine:~/Desktop# /etc/init.d/ssh start

#关闭ssh服务
root@user-virtual-machine:~/Desktop# systemctl stop ssh
或root@user-virtual-machine:~/Desktop# /etc/init.d/ssh stop

#重启ssh服务
root@user-virtual-machine:~/Desktop# systemctl restart ssh
或root@user-virtual-machine:~/Desktop# /etc/init.d/ssh restart
或root@user-virtual-machine:~/Desktop# /etc/init.d/ssh reload
或root@user-virtual-machine:~/Desktop# /etc/init.d/ssh force-reload

#开机自启ssh
root@user-virtual-machine:~/Desktop# systemctl enable ssh     
或root@user-virtual-machine:~/Desktop# /lib/systemd/systemd-sysv-install enable ssh

#关闭开机自启ssh
root@user-virtual-machine:~/Desktop# systemctl disable ssh     
或root@user-virtual-machine:~/Desktop# /lib/systemd/systemd-sysv-install disable ssh

#查看ssh状态
root@user-virtual-machine:~/Desktop# systemctl status ssh

四、问题解决

1、命令行可使用root用户，桌面不能

此处使用的gedit指令，使用vi指令也行

root@user-virtual-machine:~/Desktop# gedit /etc/pam.d/gdm-autologin
注释掉第三行内容 auth required pam_succeed_if.so user != root quiet_success

root@user-virtual-machine:~/Desktop# gedit /etc/pam.d/gdm-password
注释掉第三行内容 auth required pam_succeed_if.so user != root quiet_success

2、ssh端口已通，但是不能远程登录

在sshd_config配置中，设置成允许root登录

root@user-virtual-machine:~/Desktop# gedit /etc/ssh/sshd_config
将第34行的 PermitRootLogin prohibit-password
修改为 PermitRootLogin yes