Getting Started with AlmaLinux 9 Initial Settings

Introduction

AlmaLinux 9 is a robust and versatile Linux distribution designed to meet the needs of enterprises and individuals alike. Whether you’re setting up a server for hosting applications, managing networks, or personal projects, configuring the system with essential initial settings is critical for a secure and efficient environment.

In this guide, we’ll walk you through the fundamental initial settings for AlmaLinux 9 to ensure your system is ready for action.

Step 1: Add a New User

When installing AlmaLinux, you typically create a root user. While powerful, root access should be minimized to enhance security. Start by creating a non-root user with sudo privileges.

1. Add a new user:

   sudo adduser newuser
   

2. Set a password for the user:

   sudo passwd newuser
   

3. Grant sudo privileges:

   sudo usermod -aG wheel newuser
   

4. Verify sudo access:

   • Switch to the new user:

     su - newuser
     

   • Run a command requiring sudo:

     sudo dnf update
     

Step 2: Set Up Firewall and SELinux

AlmaLinux comes with firewalld and SELinux for enhanced security. Configuring these properly ensures your system is protected from unauthorized access.

1. Enable and start the firewall:

   sudo systemctl enable firewalld --now
   

2. Allow essential services (e.g., SSH and HTTP):

   sudo firewall-cmd --permanent --add-service=ssh
   sudo firewall-cmd --permanent --add-service=http
   sudo firewall-cmd --reload
   

3. Check SELinux status:

   sestatus
   

4. Modify SELinux mode (optional):

   • If enforcing causes issues with some applications, switch to permissive:

     sudo setenforce 0
     sudo sed -i 's/^SELINUX=enforcing/SELINUX=permissive/' /etc/selinux/config
     

Step 3: Configure Network Settings

Properly setting up your network is essential, especially for servers requiring static IPs.

1. Set a static IP using nmcli:

   nmcli connection modify eth0 ipv4.addresses 192.168.1.100/24 ipv4.gateway 192.168.1.1 ipv4.dns 8.8.8.8 ipv4.method manual
   nmcli connection up eth0
   

2. Verify network configuration:

   ip addr
   

Step 4: Enable or Disable Services

Managing services ensures your system runs only what it needs, improving performance and security.

1. List all services:

   systemctl list-unit-files
   

2. Enable a critical service (e.g., SSH):

   sudo systemctl enable sshd --now
   

3. Disable unnecessary services:

   sudo systemctl disable <service_name> --now
   

Step 5: Update the System and Add Repositories

Keeping your system up-to-date ensures you have the latest security patches and features.

1. Update AlmaLinux:

   sudo dnf update -y
   

2. Enable additional repositories (e.g., EPEL):

   sudo dnf install -y epel-release
   

Step 6: Use the Web Admin Console

AlmaLinux includes Cockpit, a powerful web-based admin console for managing your server.

1. Install Cockpit:

   sudo dnf install -y cockpit
   sudo systemctl enable cockpit.socket --now
   

2. Access the console:

   • Open a browser and navigate to:

     https://<server-ip>:9090
     

   • Log in using your server credentials.

Step 7: Customize Vim and Sudo Settings

Finally, personalizing your environment improves productivity.

1. Set up Vim preferences:

   • Create or edit ~/.vimrc:

     set number
     syntax on
     set expandtab
     set shiftwidth=4
     

2. Customize sudo behavior:

   • Edit /etc/sudoers (using visudo) to modify timeout or logging:

     Defaults timestamp_timeout=15
     

Conclusion

By completing these steps, you’ve laid a solid foundation for working with AlmaLinux 9. From user management to securing your system with firewalls and SELinux, these configurations prepare your server for advanced setups like application hosting, networking, or virtualization.

What’s Next?

In the next post, we’ll dive into time synchronization (NTP) and secure shell configurations (SSH) to ensure your server is synchronized and accessible securely.

Stay tuned, and don’t forget to share your experiences and tips in the comments below!