Introduction In today's world, where cyber threats and attacks have become more sophisticated and frequent, it is imperative to secure computer systems against malicious activities. A security audit is a systematic evaluation of the security of a computer system or network, which involves identifying potential vulnerabilities and addressing them before they are exploited by attackers. In this article, we will discuss how to perform a security audit on a Linux system using the Lynis tool. Definition of Security Auditing Security auditing refers to the process of evaluating the security posture of a computer system or network by examining its configuration ... Read More

Introduction Deploying applications to production without proper testing or validation can lead to disastrous consequences. In today's fast-paced software development environment, it is imperative to have a reliable and efficient way of releasing new features and updates, while minimizing the risk of downtime or failure. This is where Canary Deployments come into play. Canary Deployment is a technique used in software deployment for rolling out new versions of an application in small increments, rather than deploying the whole update at once. The term "canary" refers to using a small group of users as test subjects for new releases before rolling ... Read More

Introduction Secure Shell or SSH is a protocol that enables secure communication between two systems. In Linux, SSH is widely used to remotely access and manage servers. The tool establishes a secure connection between the client and server, encrypting the information being transmitted so that it can’t be intercepted by unauthorized entities. In Linux, SSH connections are created when a user logs in to a remote machine via the command-line interface. The user can execute commands on the remote host as if they were physically present on that machine. This way, system administrators and network engineers can manage multiple machines ... Read More

Introduction Linux is a popular operating system used by millions of people around the world. It offers a wide range of features and tools that are highly customizable, making it an excellent choice for power users who want to optimize their system performance. One of the most commonly used features in Linux is suspend and hibernation modes. Suspend mode is a power-saving feature that allows you to put your computer into a low-power state without shutting it down completely. In this mode, your computer will continue to consume some power, but at a much lower rate than when it ... Read More

Introduction In Linux systems, SSH (Secure Shell) is a common protocol used to connect and manage remote servers. It allows users to securely access and control their servers from anywhere in the world. The use of SSH is critical for system administrators and developers as it enables them to perform various tasks such as editing configuration files, transferring files, and managing services remotely. However, allowing root login via SSH creates significant security risks that can lead to unauthorized access and malicious attacks on your system. By disabling this feature, you can significantly reduce the chances of your Linux server ... Read More

Introduction SELinux, or Security-Enhanced Linux, is a security mechanism that is built into most modern Linux distributions, including CentOS 8. SELinux works by providing a set of mandatory access control policies that restrict access to various system resources and files. The purpose of this feature is to enhance the overall security of the system by limiting the scope of potential attacks. While SELinux is an effective tool for protecting your system, some users may want to disable it for various reasons. For instance, some applications may not work well with SELinux enabled, or it might be challenging to ... Read More

Introduction YUMDNF stands for Yellowdog Updater Modified - Dandified YUM, Next Generation. It is a package manager used in RHEL (Red Hat Enterprise Linux) and CentOS distributions to manage software packages installed on the system. Unlike the traditional YUM package manager, YUMDNF provides extensive improvements that enhance the overall functionality of this tool. Why disabling package updates may be necessary Disabling package updates may become necessary when you have an important application running on your system, and you don't want any changes to break it. In some cases, updates can cause compatibility issues with applications or dependencies that are critical ... Read More

Introduction In the world of Linux, security is a top concern for system administrators. One way to enhance security on a Linux system is by using Security-Enhanced Linux (SELinux). SELinux is a mandatory access control (MAC) system that provides an additional layer of protection for your CentOS 7 server. It provides granular access controls and policies that enable system administrators to restrict users' actions and protect sensitive data. Checking the Current Status of SELinux SELinux (Security-Enhanced Linux) is a security mechanism that offers an additional layer of protection to your system by limiting the access of processes and users to ... Read More

Introduction Firewalld is a dynamic firewall management tool that is included in CentOS 7. It replaces the previous iptables service as the default firewall tool for CentOS 7. Firewalld is designed to make it easier to manage firewall rules and provide more flexibility in defining policies and rulesets. The primary purpose of Firewalld on CentOS 7 is to protect your system from unauthorized access by blocking inbound traffic that does not match specific rules or policies. It also allows you to define different network zones with different levels of security based on the level of trust you have ... Read More

Introduction NetworkManager is a daemon that manages the network connections on Red Hat Enterprise Linux (RHEL) and its community-based counterpart, CentOS. It handles both wired and wireless connections, including ethernet, WiFi, mobile broadband, VPNs, and other network interfaces. The daemon provides a graphical user interface for managing network settings on desktop environments such as GNOME or KDE. NetworkManager is designed to automatically detect and configure connections based on the available network devices and their properties. It uses a variety of mechanisms to connect to networks dynamically, including DHCP (Dynamic Host Configuration Protocol), PPP (Point-to-Point Protocol), static IP addresses, etc. Additionally, ... Read More