Ubuntu 20.04/22.04 server environment initialization: enable the root account and enable SSH remote access

Newly installed Ubuntu servers disable root login by default, use DHCP for network interfaces, and prohibit remote root access via SSH. This article starts from scratch and walks through these three basic initial configuration tasks step by step, helping you quickly get a server environment that can be managed remotely.

⚠️Safety Tips: Allowing remote root login increases the risk of brute-force attacks. Security hardening recommendations for production environments are provided at the end of this article; please be sure to assess whether to adopt them based on your actual scenario.

• 1. Install the necessary dependencies
• 2. Enable the root account and set a password
• 3. Switch to the Root account (optional verification)
• 4. Configure a static IP (optional, suitable for server environments)
• 5. Configure SSH to allow Root remote login
• 6. Verify root remote login
• 7. Configure the command prompt color for the Root account (optional)
• Safety recommendations
• Further Reading

1. Install the necessary dependencies

A freshly installed Ubuntu 20.04/22.04 comes with only a minimal toolset by default. It is recommended to first update the software sources and install commonly used tools:

# Update the package list
sudo apt update

# Upgrade installed packages (optional)
sudo apt upgrade -y

# Install commonly used basic tools
sudo apt install -y vim curl wget net-tools git htop

Description of each tool:

tool	Purpose
vim	Text editor (than the default vi More user-friendly)
curl / wget	Network Requests and File Downloads
net-tools	Provide ifconfig,netstat and other network diagnostic commands
git	Version control tool
htop	Interactive process viewer (than top more intuitive)

💡Prompt: If you prefer nano, can vim Replace with nano. Used in subsequent steps vim The places can be replaced in the same way.

2. Enable the root account and set a password

By default, the Ubuntu root account is locked. You need to set a password first to enable it.

# Set the root user password (you will be prompted to enter the new password twice)
sudo passwd root

3. Switch to the Root account (optional verification)

After setting the password, you can switch to the root account to test whether it was successful:

su -

4. Configure a static IP (optional, suitable for server environments)

Edit the netplan configuration file:

sudo vim /etc/netplan/00-installer-config.yaml

Example configuration (modify according to the actual NIC name and network environment):

yaml

network:
  version: 2
  ethernets:
    ens160:                 # Network interface name, possibly ens33, eth0, etc.
      dhcp4: true
      addresses: 
        - 192.168.0.120/24
      gateway4: 192.168.0.1
      nameservers: 
        addresses: 
          - 114.114.114.114
          - 8.8.8.8

yaml

network:
  version: 2
  ethernets:
    ens160:
      dhcp4: false
      addresses: 
        - 192.168.0.120/24
      routes: 
        - to: default
          via: 192.168.0.1
      nameservers: 
        addresses: 
          - 114.114.114.114
          - 8.8.8.8

Application Configuration:

sudo netplan apply

5. Configure SSH to allow Root remote login

Edit SSH configuration file:

sudo vim /etc/ssh/sshd_config

Find the following line (possibly PermitRootLogin prohibit-password or PermitRootLogin no):

# PermitRootLogin prohibit-password

Change to:

PermitRootLogin yes

Restart the SSH service to make the configuration take effect:

sudo systemctl restart sshd

6. Verify root remote login

Now, you can use the root user and the previously set password to remotely log in to the server via SSH:

ssh root@your-server-IP

7. Configure the command prompt color for the Root account (optional)

After switching to the root account, the default command prompt may have no color, making it inconvenient to distinguish commands from output. You can modify ~/.bashrc to enable color display.

# Edit the root user's .bashrc file
vim /root/.bashrc

Find the following line:

# force_color_prompt=yes

the comment symbol # Remove, change to:

force_color_prompt=yes

Save and exit, then run the following command to make the configuration take effect:

source /root/.bashrc

After the configuration is complete, the root user's command prompt will be displayed in color, improving the terminal operating experience.

Safety recommendations

Allowing the root user to log in remotely poses a security risk,It is recommended to enable it only in a trusted intranet environment or during temporary maintenance. Production environment recommendations:

• Use a regular user +sudo Privilege escalation

• Configure SSH key login and disable password login

• Change the default SSH port (22 → another port)

• Install and use fail2ban Protection against brute force attacks

Okay, based on your complete sitemap, I will now recommend the most relevant further reading for this article titled "Ubuntu 20.04/22.04 Server Initialization."

Further Reading

If you are doing Ubuntu server initialization or related operations and maintenance work, the following articles may be helpful to you:

• Ubuntu 22.04 Static IP Configuration Reset After Reboot? One Trick to Fix It Completely—— After configuring a static IP, do you find the configuration lost after a reboot? This article provides an in-depth analysis of the root cause of cloud-init overwriting the Netplan configuration and offers a once-and-for-all solution.

• RockyLinux 96 Static IP Configuration Explained in Detail—— If you need to configure a static IP on a RockyLinux 96 system, this article provides complete configuration steps based on traditional network-scripts, which can be compared with Ubuntu's Netplan solution for learning.

• Guide to Configuring a Static IP in NAT Mode for Ubuntu Server in VMware—— If you deploy Ubuntu in a VMware virtual machine, this article provides a complete troubleshooting guide for static IP configuration specifically for NAT network mode, covering common issues such as network interface name identification and DNS configuration.

• Windows 11 Static IP Configuration Guide—— If you need to configure a static IP on a Windows client, this article provides detailed step-by-step instructions for both the graphical interface and the command line, suitable for reference in cross-platform network environments.

• ESXi 8.0 DNS Configuration Guide—— If your Ubuntu server runs on an ESXi virtualization platform, improper DNS configuration on the host may also cause abnormal network resolution in virtual machines. This article helps you troubleshoot network issues from the virtualization layer.