


The command line is your defense: Protect your Linux server
The command line is your defensive weapon: protect your Linux server
With the rapid development of computer technology, Linux servers have become the first choice for many enterprises and individuals. However, along with it comes an increase in cybersecurity threats. To protect our servers from hackers and malware, we need to utilize some powerful tools and techniques. The command line is one of our defensive weapons. This article will introduce some commonly used command line tools and techniques to help you protect your Linux server.
- iptables: A powerful firewall tool
iptables is a very powerful firewall tool in Linux systems that can help us filter and manage network traffic. The following are some commonly used iptables commands:
- View the current iptables rules:
iptables -L
- Allow entry and exit of specific ports:
iptables -A INPUT -p tcp --dport 80 -j ACCEPT iptables -A OUTPUT -p tcp --sport 80 -j ACCEPT
- Ban access from a specific IP address:
iptables -A INPUT -s 192.168.1.100 -j DROP
- Block all entry and exit from a specific port:
iptables -A INPUT -p tcp --dport 22 -j DROP iptables -A OUTPUT -p tcp --sport 22 -j DROP
- fail2ban : Automatically block malicious IPs
fail2ban is an automated IP blocking tool that automatically blocks malicious IP addresses based on the number of failed login attempts. We can install and configure fail2ban by following these steps:
- Install fail2ban:
sudo apt-get install fail2ban
- Edit configuration file:
sudo vi /etc/fail2ban/jail.local
In Add the following content at the end of the file:
[sshd] enabled = true port = 22 filter = sshd logpath = /var/log/auth.log maxretry = 3
- Start the fail2ban service:
sudo systemctl start fail2ban sudo systemctl enable fail2ban
- Verify whether it takes effect:
sudo fail2ban-client status sshd
- SSH configuration: Increase security
By configuring the SSH server, we can improve the security of the server. The following are some commonly used SSH configuration examples:
- Modify the SSH default port:
Edit the SSH configuration file:
sudo vi /etc/ssh/sshd_config
Find the following line and modify it to The port number you want (e.g. 2222):
#Port 22 Port 2222
- Disable root remote login:
Add the following line in the SSH configuration file:
PermitRootLogin no
- Configure SSH access restrictions:
Add the following line at the end of the SSH configuration file to only allow the specified IP address to access the SSH server:
AllowUsers user1@192.168.1.1 user2@192.168.1.2
- Restart SSH Server:
sudo systemctl restart sshd
- Use Strong Passwords: Increase Account Security
Weak passwords are a common target for hackers. To protect our servers, we should use strong password policies. Here are some tips for generating and using strong passwords:
- Use long passwords that contain uppercase and lowercase letters, numbers, and special characters.
- Use a password management tool like KeePassXC or LastPass to generate and store complex passwords.
- Change your password regularly and avoid reusing the same password across multiple websites and services.
- Update systems and applications regularly
It is important to keep systems and applications up to date as updates often include fixes for security vulnerabilities and enhancements patch. Use the following commands to update your system and applications:
- Ubuntu/Debian systems:
sudo apt-get update sudo apt-get upgrade
- CentOS/RHEL systems:
sudo yum update
Summary:
Protecting your Linux server from hackers and malware is crucial. By using command line tools and techniques, we can enhance the security of our servers. Whether it's by configuring your firewall, using tools that automatically block malicious IPs, or improving your SSH configuration and using strong passwords, you can improve your server's security. Finally, regularly update systems and applications to ensure your servers always have the latest security patches.
The above is the detailed content of The command line is your defense: Protect your Linux server. For more information, please follow other related articles on the PHP Chinese website!

MaintenanceModeinLinuxisaspecialbootenvironmentforcriticalsystemmaintenancetasks.Itallowsadministratorstoperformtaskslikeresettingpasswords,repairingfilesystems,andrecoveringfrombootfailuresinaminimalenvironment.ToenterMaintenanceMode,interrupttheboo

The core components of Linux include kernel, file system, shell, user and kernel space, device drivers, and performance optimization and best practices. 1) The kernel is the core of the system, managing hardware, memory and processes. 2) The file system organizes data and supports multiple types such as ext4, Btrfs and XFS. 3) Shell is the command center for users to interact with the system and supports scripting. 4) Separate user space from kernel space to ensure system stability. 5) The device driver connects the hardware to the operating system. 6) Performance optimization includes tuning system configuration and following best practices.

The five basic components of the Linux system are: 1. Kernel, 2. System library, 3. System utilities, 4. Graphical user interface, 5. Applications. The kernel manages hardware resources, the system library provides precompiled functions, system utilities are used for system management, the GUI provides visual interaction, and applications use these components to implement functions.

Linux maintenance mode can be entered through the GRUB menu. The specific steps are: 1) Select the kernel in the GRUB menu and press 'e' to edit, 2) Add 'single' or '1' at the end of the 'linux' line, 3) Press Ctrl X to start. Maintenance mode provides a secure environment for tasks such as system repair, password reset and system upgrade.

The steps to enter Linux recovery mode are: 1. Restart the system and press the specific key to enter the GRUB menu; 2. Select the option with (recoverymode); 3. Select the operation in the recovery mode menu, such as fsck or root. Recovery mode allows you to start the system in single-user mode, perform file system checks and repairs, edit configuration files, and other operations to help solve system problems.

The core components of Linux include the kernel, file system, shell and common tools. 1. The kernel manages hardware resources and provides basic services. 2. The file system organizes and stores data. 3. Shell is the interface for users to interact with the system. 4. Common tools help complete daily tasks.

The basic structure of Linux includes the kernel, file system, and shell. 1) Kernel management hardware resources and use uname-r to view the version. 2) The EXT4 file system supports large files and logs and is created using mkfs.ext4. 3) Shell provides command line interaction such as Bash, and lists files using ls-l.

The key steps in Linux system management and maintenance include: 1) Master the basic knowledge, such as file system structure and user management; 2) Carry out system monitoring and resource management, use top, htop and other tools; 3) Use system logs to troubleshoot, use journalctl and other tools; 4) Write automated scripts and task scheduling, use cron tools; 5) implement security management and protection, configure firewalls through iptables; 6) Carry out performance optimization and best practices, adjust kernel parameters and develop good habits.


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

PhpStorm Mac version
The latest (2018.2.1) professional PHP integrated development tool

ZendStudio 13.5.1 Mac
Powerful PHP integrated development environment

WebStorm Mac version
Useful JavaScript development tools

Safe Exam Browser
Safe Exam Browser is a secure browser environment for taking online exams securely. This software turns any computer into a secure workstation. It controls access to any utility and prevents students from using unauthorized resources.

Notepad++7.3.1
Easy-to-use and free code editor