How to Diagnose and Fix Slow DNS Resolution on Linux
Improve Linux network performance by diagnosing and fixing slow DNS resolution. Learn step-by-step troubleshooting, CLI commands, and configuration fixes to speed up DNS lookups on any Linux distribution. Table of Contents 🔈Introduction Slow DNS resolution can make even the fastest Linux system feel sluggish. When domain lookups stall, websites load slowly, package managers hang on […]
How to Run GUI Applications Remotely over SSH with X11 Forwarding / Waypipe
Learn how to run Linux GUI applications remotely over SSH using X11 forwarding or Waypipe. Includes setup steps, CLI examples, performance tips, security advice, and comparison charts for choosing the right method. Table of Contents 🔈Introduction Running graphical Linux applications on a remote server and displaying them on your local machine can be transformative for […]
Harden SSH on Ubuntu 24.04: Disable Root, Use Key Auth, Restrict IPs
Learn how to harden SSH on Ubuntu 24.04. Disable root login, enforce SSH key authentication, and restrict IP access for maximum protection. Table of Contents 🔈Introduction Secure Shell (SSH) is the backbone of remote system management, but an exposed or misconfigured SSH service is a prime target for attackers. Ubuntu 24.04, as a modern Linux […]
Splunk Email Security Risk: How to Fix allowedDomainList Warning in alert_actions.conf
Learn how to fix the Splunk allowedDomainList security warning in alert_actions.conf. Prevent unauthorized alert emails and protect sensitive data by configuring domain restrictions correctly. Table of Contents 🔈Introduction Splunk administrators often encounter a critical security warning: ⚠️ Found an empty value for ‘allowedDomainList’ in the alert_actions.conf configuration file. This alert points to a significant security misconfiguration […]
How to Monitor SSH Logins Using Auditd and Logwatch
Learn how to monitor SSH logins using Auditd and Logwatch on Linux. This step-by-step guide covers setup, configuration, log analysis, and reporting to enhance server security. Table of Contents 🔈Introduction Secure Shell (SSH) is one of the most widely used methods for remote server administration. Because it provides a gateway into critical infrastructure, monitoring SSH […]
Configure a Firewall using UFW (Ubuntu) and Firewalld (RHEL)
Learn how to configure a Linux firewall using UFW on Ubuntu and Firewalld on RHEL. Step-by-step CLI examples, best practices, and comparison tables included. Table of Contents 🔈Introduction Securing your Linux server is a critical step in system administration. One of the foundational layers of server security is the firewall — a system that controls […]
Fixing the Apache Error: Invalid Command ‘Header’
Learn how to fix the Apache error “Invalid command ‘Header’” when configuring a web server. Step-by-step guide with CLI commands, configuration examples, and troubleshooting tips to get your Apache server running smoothly. Table of Contents 🔈Introduction When running a web server, nothing is more frustrating than Apache failing to start because of a cryptic configuration […]
Install XRDP on Ubuntu 24.04 for Remote Desktop Access
Learn how to install and configure XRDP on Ubuntu 24.04 LTS to enable secure remote desktop access from Windows, macOS, or Linux. Step‑by‑step setup with firewall rules, troubleshooting tips and performance/security best practices. Table of Contents 🔈Introduction Remote desktop access to Linux machines is essential for administrators, remote workers, developers, or anyone needing GUI access […]
Upgrade to PHP 8.4 on Ubuntu 22.04 | 24.04
Upgrade to PHP 8.4 on Ubuntu 22.04 or 24.04 with this complete, step‑by‑step guide. Includes commands, configuration, Apache & Nginx setup, troubleshooting, and best practices to ensure a smooth migration. Table of Contents 🔈Introduction Modern PHP releases bring faster execution, new features, and better security. PHP 8.4, though still developing in mid‑2025, is increasingly adopted by developers. If you’re […]
How to Enable Fail2Ban to Block Repeated Failed Login Attempts on Linux
Learn how to configure Fail2Ban to block repeated failed login attempts on Linux. Step-by-step guide with commands, configuration examples, and security tips for SSH and other services. Table of Contents 🔈Introduction In today’s threat landscape, brute-force attacks are a common way attackers attempt to gain unauthorized access to Linux servers. A simple and effective defense […]