Security & Hardening

Why Your Linux System Boots into grub rescue> and How to Fix It 0
- Best Practices & Patterns, Linux Basics, Security & Hardening, System Administration, Troubleshooting, Web Servers
- August 27, 2025
It can be deeply frustrating when a Linux system fails to boot properly and drops into a grub rescue> prompt. This usually indicates a problem with the GRUB (GRand Unified Bootloader), the software responsible for booting the OS. This guide will help you understand why this happens and how to recover your system—even if you’re using RHEL 7, 8, 9, or 10
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How to Configure HTPasswd Authentication on an OpenShift Cluster 0
- Best Practices & Patterns, Containers & Docker, DevOps Tools, Kubernetes, Security & Hardening, System Administration, Troubleshooting, Virtualization
- August 19, 2025
In this step-by-step guide, we will configure HTPasswd authentication on an existing OpenShift 4.15+ single-node cluster. We’ll create user accounts, update the cluster’s OAuth settings to use HTPasswd, and verify access via both the CLI and the web console. We’ll also cover how to assign admin privileges to a new user and remove the default kubeadmin user for security.
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Linux Active Directory Integration with SSSD, SSH, and PAM – Guide 0
- Best Practices & Patterns, Linux Basics, Security & Hardening, System Administration, Troubleshooting
- August 5, 2025
By following these practices and understanding the components, you will have a robust setup where Linux and Active Directory work together for seamless user authentication. The key is to verify each piece (DNS, Kerberos, SSSD, PAM) and use the tools available (logs, realm commands, sssctl, etc.) to diagnose issues. With proper configuration, domain users can log into Linux systems using their AD accounts, and administrators can centrally manage credentials and policies in AD while maintaining Linux-specific settings via SSSD.
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Installing and Using Shodan CLI on Linux: A Complete Walkthrough 0
- Linux Basics, Monitoring & Logging, Networking, Security & Hardening, System Administration, Troubleshooting, Web Servers
- June 7, 2025
Shodan is a powerful search engine designed to find internet-connected devices across the globe. It goes beyond conventional search engines by enabling the discovery of specific hardware and software configurations. This guide covers installing and effectively using Shodan’s Command-Line Interface (CLI) on Linux systems including Debian-based (like Ubuntu) and CentOS/RHEL.
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How to Investigate and Resolve SELinux Issues in Linux 0
- Best Practices & Patterns, Linux Basics, Security & Hardening, System Administration, Troubleshooting, Web Servers
- June 7, 2025
SELinux (Security-Enhanced Linux) is a powerful security feature of Red Hat Enterprise Linux and CentOS. It provides a mechanism to enforce mandatory access control policies. However, SELinux can occasionally block legitimate activities if misconfigured. Here’s how you can investigate and resolve SELinux issues effectively.
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How to Troubleshoot and Recover a Linux System That Won’t Boot 0
- Configuration Management, Linux Basics, Security & Hardening, System Administration, Web Servers
- May 29, 2025
When a Linux system refuses to boot, it can be daunting – but a methodical approach will often get you back up and running. This guide provides step-by-step troubleshooting for common boot issues on Ubuntu, CentOS, and RHEL, suitable for intermediate Linux users. We’ll cover preliminary checks (like hardware and BIOS/UEFI settings), using recovery
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