How to Set Up SSH Server on Linux

Secure Shell (SSH) is a protocol used to securely access and manage networked devices over an unsecured network. Setting up an SSH server allows you to remotely access your Linux machine securely. This tutorial will guide you through the steps to install and configure an SSH server using OpenSSH on Linux.

1. Installing OpenSSH Server

OpenSSH is the most widely used SSH server implementation. To set it up, first, you need to install the OpenSSH server package:

• For Ubuntu:

  sudo apt update
  sudo apt install openssh-server

• For CentOS:

  sudo yum install openssh-server

2. Starting and Enabling the SSH Service

After installation, start the SSH service using the following command:

sudo systemctl start sshd

To ensure that the SSH service starts on boot, enable it with:

sudo systemctl enable sshd

3. Configuring the SSH Server

The main configuration file for the SSH server is located at /etc/ssh/sshd_config. You can customize its settings according to your security requirements:

sudo nano /etc/ssh/sshd_config

Common settings to consider adjusting include:

• Port: Change the default port (22) to something else for security reasons.
• PermitRootLogin: Set to no to prevent root login.
• PasswordAuthentication: Consider using no to require SSH key authentication instead.

After editing, save the file and exit the text editor.

4. Restarting the SSH Service

To apply the changes made to the configuration file, restart the SSH service with:

sudo systemctl restart sshd

5. Testing the SSH Server

To test the SSH server from another machine, use the following command:

ssh username@your_server_ip

Replace username with your actual username on the server and your_server_ip with the server’s IP address.

6. Securing Your SSH Server

To enhance the security of your SSH server, consider the following practices:

• Use SSH keys for authentication instead of passwords.
• Install and configure a firewall to restrict access to the SSH port.
• Regularly update your server and OpenSSH to patch vulnerabilities.

7. Conclusion

By following this tutorial, you have successfully set up an SSH server on your Linux machine. SSH is a powerful tool for remote management, and securing it properly enhances the safety of your data and systems. Continue to explore SSH configurations and best practices for maintaining secure access to your servers!

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Dorian Kane

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