With the launch of Security Engine 1.0.x, we enabled the Security Engine to function as an HTTP REST API, allowing it to gather signals from other Security Engines.

I will guide you through the steps to set up the CrowdSec Security Engine across multiple servers, where one server will serve as the parent and two additional machines will forward alerts to it.

Benefits

Sharing cybersecurity incidents across machines using the CrowdSec Security Engine is a highly effective strategy to enhance collective security defenses. By leveraging CrowdSec's capability to distribute remediations among connected machines, each machine benefits from real-time updates about new threats detected elsewhere in the network.

Architecture

In the diagram above, the parent Security Engine, designated as server-1, will be set up as the HTTP REST API, commonly known as the LAPI (Local API). This engine will be in charge of storing and distributing the gathered signals. Remediation is managed through the Remediation Components, which depend on the LAPI offered by server-1. It's crucial to understand that mitigation can occur independently from detection.

Server-2 and server-3 are designated as internet-facing machines that will host services available to the public and will be known as the child Log Processors. On these servers, we will install CrowdSec Security Engine and Remediation Components, which will interact with the server-1 LAPI.

Note: The phrase child Log Processors refers to a CrowdSec Security Engine that operates with its LAPI turned off. For more information on this, consult our Taxonomy Update Article.

We strongly encourage you to explore the CrowdSec Hub to learn about the extensive range of services the Security Engine can protect. This platform showcases the diverse capabilities of the Engine in securing everything from web applications to databases against cyber threats.

Introduction

In the realm of Linux distributions, Debian stands out for its stability, security, and rich repository of software packages. Managing these packages efficiently is fundamental to maintaining system integrity and ensuring software runs smoothly. Central to this management is DPKG, Debian's package manager, a tool that often works behind the scenes but is incredibly powerful when used directly. This guide dives into the world of DPKG, offering insights from basic usage to advanced management techniques.

Understanding DPKG and Its Ecosystem

DPKG (Debian Package) is the core package management system in Debian-based Linux distributions. It is responsible for installing, removing, and providing information about .deb packages, the format used by Debian packages.

DPKG does not operate in isolation; it is part of a larger ecosystem of tools designed to make package management more manageable and automated. While DPKG deals directly with package files, APT (Advanced Package Tool) and other utilities work at a higher level, handling repositories and automatic dependency resolution. Understanding DPKG's role within this ecosystem is crucial for mastering package management in Debian.

Setting Up Your Environment for DPKG

Before delving into DPKG's operations, ensure your Debian system is up-to-date. Running sudo apt update && sudo apt upgrade will refresh your package lists and upgrade the existing packages to their latest versions. Verifying DPKG's installation and version can be achieved with dpkg --version, which is essential for compatibility and troubleshooting.

Basic DPKG Operations

To install a package, the command sudo dpkg -i package_file.deb is used. This command requires the path to a .deb file, which DPKG will then unpack and install. One of the nuances of using DPKG directly is handling dependencies; DPKG will notify you of any missing dependencies but will not fetch them automatically.

Removing software with DPKG can be done with sudo dpkg -r package_name. If you wish to remove the package along with its configuration files, the purge option (sudo dpkg -P package_name) is your go-to command.

To list all installed packages, dpkg -l is incredibly useful. For checking if a specific package is installed, dpkg -l | grep package_name narrows down the search efficiently.

Linux stands at the heart of countless operating systems, driving everything from personal computers to servers and embedded systems across the globe. Its flexibility and open-source nature allow for extensive customization, much of which is achieved through the adept manipulation of kernel parameters. These boot options are not just tools for the Linux connoisseur but essential instruments for any user seeking to optimize and troubleshoot their systems. This guide demystifies kernel parameters, illustrating their importance, common uses, and methods for modification.

Understanding Kernel Parameters

Kernel parameters, often referred to as boot options, are settings or arguments passed to the Linux kernel at the time of system boot. These parameters can control a wide range of system behaviors, from hardware compatibility and device management to system security and performance characteristics. By adjusting these parameters, users can tailor the operating system to meet their specific needs or resolve issues that may arise during the boot process.

Commonly Used Kernel Parameters

A myriad of kernel parameters exist, each serving a unique purpose. Some of the most commonly used include:

• quiet: Reduces the verbosity of the kernel messages during boot, leading to a cleaner boot process. This is useful for users who prefer a minimalistic boot screen.
• splash: Works in conjunction with quiet to display a graphical boot splash screen instead of textual boot messages.
• nomodeset: Prevents the kernel from loading video drivers until after the boot process is complete. This parameter can be invaluable when troubleshooting display issues.
• ro and rw: Dictate whether the root filesystem is mounted as read-only (ro) or read-write (rw) during boot. ro is often used during system maintenance to protect filesystem integrity.

How to Modify Kernel Parameters

For temporary modifications—lasting only for the current boot session—parameters can be adjusted through the boot loader. Here’s how: