Linux Server Security: Best Practices for Running Essential Commands

Linux is an open source operating system that is widely used in server environments. Due to its high degree of customizability and reliability, Linux servers have become the operating system of choice for many businesses and organizations. However, like any other operating system, Linux servers face various security threats. In order to ensure the security of the server, administrators need to take a series of measures and best practices using necessary commands. This article will introduce some commonly used Linux server security commands and best practices.

1. Update system and software: Regularly updating your Linux server’s operating system and software is one of the key steps to keep your server secure. Use the following command to update your system:

   sudo apt update
   sudo apt upgrade

   This will help you keep your system and software up to date, fixing known security vulnerabilities and providing better security.

2. Create strong passwords: Using strong passwords can effectively prevent hackers from cracking them. Use the following command to create and manage passwords:

   passwd 用户名

   Make sure the password is at least 8 characters long and contains uppercase letters, lowercase letters, numbers, and special characters.

3. Disable root login: Using the root account to log in to the server may pose a security threat. The best practice is to disable root login and log in to the server as a normal user, and then use the following command to escalate privileges:

   sudo su -

   This can reduce the risk of the system being hacked.

4. Restrict SSH access: SSH is a common protocol for remotely managing Linux servers. To increase security, you can take the following steps:
5. Change the SSH default port: Edit the SSH configuration file /etc/ssh/sshd_config and set Port to a non- Default port.
6. Disable root login: Add PermitRootLogin no to the SSH configuration file to prohibit root users from logging in through SSH.
7. Restrict user access: Add AllowUsers username to the SSH configuration file to only allow specific users to access via SSH.
8. Use a firewall: Configuring a firewall is one of the important measures to protect the Linux server. Use the following command to configure the firewall:

9. Install the firewall software:

   sudo apt install ufw

10. Enable the firewall:

    sudo ufw enable

11. Configure Firewall rules:

    sudo ufw allow 22    # 允许SSH连接
    sudo ufw allow 80    # 允许HTTP连接
    sudo ufw allow 443   # 允许HTTPS连接

    Ensure that only necessary ports are opened and access is restricted.

12. Regularly back up data: Regularly backing up the important data of the server is one of the key steps to restore the server. Use the following command to create a scheduled backup:

    tar -czvf backup.tar.gz /path/to/directory

    Replace /path/to/directory with the path to the directory you want to back up. You can use cron to implement automatic backup.

13. Monitor server logs: Regularly monitoring server logs can help administrators detect and identify potential security threats. Use the following command to view the server log:

    tail -f /var/log/syslog

    This command will display the end of the system log in real time.

14. Install security software: Installing specialized security software can further enhance the security of the server. For example, Fail2Ban can prevent brute force password cracking, ClamAV can detect malware, Snort can detect intrusions, etc.

Summary:
Protecting the security of Linux servers is an important task that administrators should consider. This article introduces some common Linux server security commands and best practices, including updating systems and software, creating strong passwords, disabling root logins, restricting SSH access, using firewalls, backing up data regularly, monitoring server logs, and installing security software. By taking these measures and best practices, you can improve the security of your Linux server and reduce the risk of your server being attacked.

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