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

In today's digital age, internet connectivity plays a crucial role in our day-to-day lives. In order to connect to the internet, we need an address that identifies us on the network. This is where IP addresses come into play. IPv4 (Internet Protocol version 4) is the fourth version of IP addresses and has been used for many years. However, as technology advances and more devices connect to the internet, the number of available IPv4 addresses is running out. That's why IPv6 was introduced. Explanation of What IPv6 Is and Why Someone May Want to Disable It IPv6 (Internet Protocol version ... Read More

In today's modern world, the utilization of the Internet is essential for many businesses and individuals alike. The Internet Protocol (IP) is a fundamental communication protocol that is used to connect devices over the internet. Internet Protocol Version 6 (IPv6) was introduced in 1998 as an improvement over IPv4 and has since become more widely adopted. Explanation of what IPv6 is and why someone may want to disable it IPv6 provides several advantages over its predecessor, including a larger address space, improved security, and better network performance. However, there are situations where disabling IPv6 may be necessary. For example, some ... Read More

Introduction When it comes to system security, it is essential to restrict root access as much as possible, especially when multiple users have access to the system. One of the ways a user can gain root access is by invoking the “su” command. While the su command allows a user to switch from one user account to another, it can be misused or abused by users with sudo privileges. In this article, we will explain what “su” access for sudo users means, why it's important to disable "su" access for sudo users and how you can do this. ... Read More

Introduction Linux is an open-source operating system that is widely used by developers, system administrators, and individuals who prefer a non-proprietary operating system. A Linux distribution, often simply called a "distro, " is a customized version of the Linux operating system that includes different software packages and configurations to fit specific needs. There are hundreds of Linux distributions available, ranging from popular ones like Ubuntu and Fedora to specialized ones like Kali Linux for cybersecurity professionals. Planning Your Distribution Identifying your goals and target audience Before starting, it is essential to identify your goals and target audience. What do you ... Read More