The most commonly used Linux commands: improving your server security

The most commonly used Linux commands: improve your server security

In today's Internet era, server security is crucial. As server managers, we must take a series of measures to protect our servers from malicious attacks and potential threats. Being familiar with and using some of the most commonly used Linux commands can not only improve our work efficiency, but also enhance the security of the server. This article will introduce some of the most commonly used Linux commands and provide corresponding code examples.

1. Update system:
   Running timely system updates on the server is an important part of ensuring server security. Use the following commands to update installed packages and system kernel.

   sudo apt update  # 更新软件包列表
   sudo apt upgrade  # 更新已安装的软件包
   sudo apt dist-upgrade  # 升级系统内核

2. Firewall settings:
   Firewall can help filter and control inbound and outbound network traffic and improve server security. In Linux, there are many firewall tools to choose from, such as ufw and iptables. The following is an example based on ufw:

   sudo ufw allow ssh  # 允许SSH连接
   sudo ufw enable  # 启用ufw防火墙
   sudo ufw status  # 查看ufw防火墙状态

3. Find malicious processes:
   In the case of a server being compromised, there may be malicious processes running. Use the following commands to find and kill these processes.

   ps -ef | grep <process_name>  # 查找指定进程名
   sudo kill <pid>  # 终止指定进程

4. Install and update packages:
   Regularly updating and installing packages can fix known vulnerabilities and improve server security. Use the following commands to install new packages and update installed packages.

   sudo apt install <package_name>  # 安装指定软件包
   sudo apt remove <package_name>  # 卸载指定软件包
   sudo apt autoremove  # 自动删除不再需要的依赖关系
   sudo apt update  # 更新软件包列表
   sudo apt upgrade  # 更新已安装的软件包

5. Add users and set permissions:
   Proper management and permission settings for users on the server are the key to ensuring server security. Here are some example commands for user management and permission settings.

   sudo adduser <username>  # 添加新用户
   sudo deluser <username>  # 删除用户
   sudo usermod -aG sudo <username>  # 将用户添加到sudo组
   sudo chmod 600 <file_name>  # 设置文件权限为只读

Summary:
This article introduces some of the most commonly used Linux commands and provides corresponding code examples. By mastering and using these commands, we can improve the security of our servers and protect our servers from malicious attacks and potential threats. However, this is only the first step in securing your server. As server managers, we should regularly update the system, set appropriate firewall rules, monitor server activities, and take other necessary security measures to ensure the long-term safe operation of the server.

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