centos和ubuntu配置区别

一、root用户

1. centos在安装过程中设置root用户
2. ubuntu先创建user，登录系统后，输入语句设置root密码

sudo passwd root

二、ssh服务启动

ubuntu在用客户端ssh连接时，先连接到创建的user，再切换到root用户

centos的ssh默认安装？

ubuntu

1.查看ssh是否启动

ps -ef | grep ssh

2.查看ssh是否安装

sudo /etc/init.d/ssh restart

3.安装ssh服务器

sudo apt-get install openssh-server

4.如果安装报错 Package ‘xxx’ has no installation candidate

• 备份/etc/apt/sources.list

  sudo cp -i /etc/apt/sources.list /etc/apt/sources.list.backup
  

• 更新repos

  vi /etc/apt/sources.list
  #添加以下内容
  deb http://mirrors.aliyun.com/ubuntu/ xenial main restricted universe multiverse
  deb http://mirrors.aliyun.com/ubuntu/ xenial-security main restricted universe multiverse
  deb http://mirrors.aliyun.com/ubuntu/ xenial-updates main restricted universe multiverse
  deb http://mirrors.aliyun.com/ubuntu/ xenial-proposed main restricted universe multiverse
  deb http://mirrors.aliyun.com/ubuntu/ xenial-backports main restricted universe multiverse
  deb-src http://mirrors.aliyun.com/ubuntu/ xenial main restricted universe multiverse
  deb-src http://mirrors.aliyun.com/ubuntu/ xenial-security main restricted universe multiverse
  deb-src http://mirrors.aliyun.com/ubuntu/ xenial-updates main restricted universe multiverse
  deb-src http://mirrors.aliyun.com/ubuntu/ xenial-proposed main restricted universe multiverse
  deb-src http://mirrors.aliyun.com/ubuntu/ xenial-backports main restricted universe multiverse
  

• 更新apt-get

  sudo apt-get update
  

• 安装启动

  sudo apt-get install openssh-server
  sudo /etc/init.d/ssh start
  

三、遇到问题

1、ping www.baidu.com 报错

错误情况：

ping: www.lxx1.com: Temporary failure in name resolution
ping: www.lxx1.com: System error
ping: www.lxx1.com: Unknown host www.baidu.com

解决方法

• 确认已配置好DNS：

1. 方法一：vi /etc/resolv.conf 添加

   nameserver 114.114.114.114
   nameserver 223.5.5.5
   

2. 方法二：vi /etc/sysconfig/network-scripts/ifcfg-*** 添加

DNS1=114.114.114.114
DNS2=223.5.5.5

• 查看 vi /etc/nsswitch.conf 修改
  hosts: files dns

• 查看防火墙有没有把dns的53端口限制住了

1. netstat -anp | grep 53
2. 没看，运行systemctl iptables stop 关闭防火墙试试，可行，进行第3步
3. 防火墙开放53端口
   iptables -I INPUT -p tcp --dport 3306 -j ACCEPT