023. Ubuntu common personalized configuration

Root login settings##

Ubuntu closes the root account by default, and root login can be turned on or off according to the actual situation.

ubuntu@localhost:~$ sudo apt install openssh-server
ubuntu@localhost:~$ sudo passwd root
New password:【enter password】
Retype newpassword:【enter password】
ubuntu@localhost:~$ sudo vim /etc/ssh/sshd_config
……
Port 22                                             #SSH port
……
PermitRootLogin yes                                 #Allow root user to log in
# PermitRootLogin no                                 #Prohibit root user login
PasswordAuthentication yes                          #Allow password login
# PasswordAuthentication no                          #Prohibit password login, such as using public key login
……
ubuntu@localhost:~$ sudo systemctl restart sshd     #Restart the sshd service

Modify DNS

It is recommended to modify the dns to the address of the domestic mainstream dns service provider, such as Alibaba Cloud dns.

root@localhost:~# vi /etc/netplan/50-cloud-init.yaml
network:
 ethernets:
  eth0:
   addresses:-172.24.8.111/24
   dhcp4:false
   gateway4:172.24.8.2
   nameservers:
    addresses:-223.5.5.5                 #Modify DNS to Alibaba Cloud public dns
    search:[]
 version:2

Modify apt source##

It is recommended to modify the apt source to the address of the domestic mainstream apt provider, such as Alibaba Cloud apt source.

root@localhost:~# sudo vim /etc/apt/sources.list
deb http://mirrors.aliyun.com/ubuntu/ focal main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ focal main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ focal-security main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ focal-security main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ focal-updates main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ focal-updates main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ focal-proposed main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ focal-proposed main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ focal-backports main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ focal-backports main restricted universe multiverse

More reference: https://developer.aliyun.com/mirror/ubuntu

Update system##

root@localhost:~# apt-get update && apt-get upgrade -y && apt-get autoremove -y

Install common server software##

root@localhost:~# sudo apt-get-y install net-tools vim wget ntp bash-completion build-essential gcc openssh-client lvm2 make terminator git ssh lrzsz htop

The above are mainly server-related software, and the necessary components can be installed according to the actual situation.

Modify locale##

root@localhost:~# sudo vi /etc/default/locale
LANG="zh_CN.UTF-8"
LANGUAGE="zh_CN:zh"                 #Set to Chinese

LANG="en_US.UTF-8"  
LANGUAGE="en_US:en"                 #Need to be in English

Create new user and key-free configuration##

Create user###

root@localhost:~# adduser xianghy   #Fill in the relevant information to create a user

Login test###

[ root@client ~]# ssh [email protected]       #Client test login
[email protected]'s password:【enter password】

Key-free login###

[ root@client ~]# ssh-keygen -f ~/.ssh/xianghy_key -N ''                         #Client creates private key
[ root@client ~]# ssh-copy-id -i ~/.ssh/xianghy_key.pub [email protected]     #Upload the public key to the server

Client configuration login alias###

[ root@client ~]# vim ~/.ssh/config
Host xianghyhost                    #Host alias
 HostName 172.24.8.111           #Server IP
 Port 22                         #Server SSH port
 User xianghy                    #Server user name
 IdentityFile ~/.ssh/xianghy_key #Private key file path
[ root@client ~]# chmod 600~/.ssh/config

Key-free login test###

[ root@client ~]# ssh xianghyhost    #Use alias login test

Turn off the firewall##

root@localhost:~# systemctl stop ufw.service
root@localhost:~# systemctl disable ufw.service

Clock server configuration##

chrony service configuration###

Reference: "001.Chrony Time Server"