Troubleshooting on Linux Security

Resolving DNS Issues with resolvectl and systemd-resolved in a Home Network

Mon, 15 Jun 2026 09:54:03 +0200

Introduction to DNS Resolution

When setting up a home network, DNS resolution is one of those critical components that can be a real pain to troubleshoot. I’ve seen this go wrong when people are new to Linux, so let’s dive into how to use resolvectl to resolve DNS issues with systemd-resolved.

Understanding systemd-resolved

systemd-resolved is a system service that handles DNS resolution, among other network-related tasks. It’s part of the systemd suite and is widely used in many Linux distributions, including Ubuntu, Debian, and Fedora. The real trick is that systemd-resolved provides improved DNS security and better support for modern DNS protocols like DNS over TLS (DoT) and DNS over HTTPS (DoH). Don’t bother with trying to use it without understanding these benefits, as they’re a key part of what makes systemd-resolved so useful.

Troubleshooting Slow Network Connectivity with ss and resolvectl on Linux

Sun, 14 Jun 2026 08:16:06 +0200

Introduction to Network Troubleshooting

I’ve seen my fair share of slow network connectivity issues on Linux, and having the right tools at your disposal can make all the difference. Two tools that I rely on are ss and resolvectl, which can help you diagnose and troubleshoot network issues. In this article, we’ll explore how to use these tools to identify and potentially fix slow network connectivity problems.

Understanding `ss`

The ss command is a replacement for the traditional netstat command, and it provides more detailed information about network connections, including TCP, UDP, and Unix domain sockets. To get started with ss, you can use the following command to display all active connections:

Resolving Dependency Conflicts When Mixing Third-Party Repositories with Distribution Packages

Thu, 11 Jun 2026 09:22:32 +0200

Introduction to Dependency Conflicts

I’ve seen this go wrong when mixing third-party repositories with distribution packages - dependency conflicts can cause frustration and potential security risks. As a Linux user, understanding how to resolve these conflicts is crucial for maintaining a stable and secure system. In this article, we’ll explore the common causes of dependency conflicts, how to identify them, and practical steps to resolve them.

Understanding Dependency Conflicts

Dependency conflicts occur when two or more packages require different versions of the same dependency. This can happen when you install packages from third-party repositories, which may not be compatible with the distribution’s packages. For example, if you’re running Ubuntu 22.04 and want to install the latest version of ffmpeg from a third-party repository, it can cause a conflict because the repository requires a newer version of libavcodec than what’s available in Ubuntu 22.04.

Troubleshooting Poor Video Performance on Linux Laptops with Hybrid Graphics and Wayland

Wed, 10 Jun 2026 08:29:11 +0200

Introduction to Troubleshooting

When dealing with Linux laptops that have hybrid graphics, getting the best video performance can be tough, especially with Wayland. I’ve seen this go wrong when people don’t take the time to understand how their system is set up. As of 2026, many Linux distributions have made big strides in supporting hybrid graphics and Wayland, but issues still pop up. In this article, we’ll go over some practical steps for troubleshooting poor video performance on these laptops.

Troubleshooting Common Connection Issues with resolvectl and ss on Linux

Mon, 08 Jun 2026 11:07:29 +0200

Introduction to Troubleshooting Connection Issues

When working with Linux, connection issues can arise due to various reasons such as misconfigured DNS settings, firewall rules, or network interface configurations. I’ve seen this go wrong when a simple DNS misconfiguration can bring down an entire application. To troubleshoot these issues, Linux provides a range of tools, including resolvectl and ss. In this article, we will explore how to use these tools to diagnose and resolve common connection problems.

Troubleshooting Disk Usage Issues with Duplicate Files and Unnecessary Logs on Btrfs and Ext4 Filesystems

Sat, 06 Jun 2026 09:38:34 +0200

Introduction to Disk Usage Issues

I’ve seen disk usage issues plague even the most well-maintained Linux systems, often due to duplicate files and unnecessary logs. As of 2026, both Btrfs and Ext4 filesystems are widely used, each with their own set of tools and best practices for troubleshooting and resolving these issues. In this article, we’ll delve into practical steps for identifying and addressing duplicate files and unnecessary logs on both Btrfs and Ext4 filesystems, focusing on current tools and methodologies.

Rescuing a Linux System Stuck in Emergency Mode: A Step-by-Step Recovery Guide

Wed, 03 Jun 2026 11:47:11 +0200

Introduction to Emergency Mode

I’ve seen this go wrong when a Linux system encounters a critical issue during boot - it may enter Emergency Mode. This mode provides a minimal environment for troubleshooting and recovery. With many Linux distributions, including Debian and Arch Linux, updating their boot processes to use systemd, understanding how to rescue a system stuck in Emergency Mode is crucial.

Identifying the Issue

To rescue a system in Emergency Mode, you first need to identify the cause of the issue. Don’t bother with guessing - check the system logs, which are usually available in the /var/log directory. I usually start with the journalctl command to view the system logs:

Troubleshooting Failed Mounts at Boot Time with systemd and fstab

Tue, 02 Jun 2026 09:15:54 +0200

Introduction to Troubleshooting Failed Mounts

When I’m dealing with a Linux system that won’t boot properly, one of the first things I check is the mount points. systemd and the /etc/fstab file are crucial in this process, but issues can still arise, leading to failed mounts and potential system instability. In this article, I’ll walk you through practical steps to troubleshoot and resolve failed mounts at boot time, focusing on systemd and fstab configurations.

Rescuing a Broken Linux System with a systemd Emergency Mode Shell

Sun, 31 May 2026 08:26:25 +0200

Introduction to Emergency Mode

I’ve seen this go wrong when a Linux system encounters a critical issue during boot - it can be a real headache. But, thankfully, Linux has a built-in safety net called emergency mode. This mode kicks in when there’s a failed filesystem check or an inability to mount a necessary partition, providing a minimal environment for troubleshooting and repair. With the advancements in Linux, understanding how to use emergency mode is crucial for system administrators and users alike.

Troubleshooting Slow DNS Lookups with systemd-resolved and resolvectl

Mon, 25 May 2026 08:57:59 +0200

Introduction to Troubleshooting Slow DNS Lookups

I’ve seen slow DNS lookups bring Linux systems to a crawl, and with our increasing reliance on online services, efficient DNS resolution is crucial. This article focuses on troubleshooting slow DNS lookups using systemd-resolved and resolvectl, which are integral to many modern Linux distributions.

Understanding systemd-resolved

systemd-resolved is a system service that provides DNS resolution, replacing traditional implementations like glibc’s resolver. It offers improved security, better DNSSEC handling, and efficient management of multiple DNS servers. To check if it’s running on your system, use:

Troubleshooting Broken Dependencies After Adding a Third-Party Repository

Wed, 20 May 2026 09:28:17 +0200

Introduction to Dependency Troubleshooting

I’ve seen this go wrong when adding third-party repositories to a Linux system - it’s a great way to get the latest software, but it can also lead to broken dependencies and a whole lot of frustration. In this article, I’ll walk you through the practical steps to troubleshoot and resolve broken dependencies after adding a third-party repository.

Understanding Dependencies

Before we dive into troubleshooting, let’s take a step back and understand how dependencies work in Linux. Dependencies are packages that a particular package requires to function correctly. When you install a package, the package manager (such as apt or dnf) will automatically install any required dependencies. However, when adding third-party repositories, the package manager may not always be able to resolve dependencies correctly, leading to broken packages. Don’t bother with trying to manually resolve these dependencies - it’s a recipe for disaster.

Troubleshooting systemd Service Startup Failures with Dependency Ordering and Journalctl

Mon, 18 May 2026 10:30:29 +0200

Introduction to systemd Service Troubleshooting

I’ve seen this go wrong when services fail to start due to complex dependency ordering and logging issues. systemd, with its powerful tools for diagnosing problems, makes it easier to identify and fix these issues. In this article, we’ll focus on practical examples of using dependency ordering and journalctl to troubleshoot systemd service startup failures.

Understanding systemd Dependencies

systemd services are defined in unit files, typically located in /etc/systemd/system/ or /usr/lib/systemd/system/. These files specify the service’s dependencies, which are crucial for determining the order in which services start. Dependencies are defined using directives like Requires, Wants, Before, and After. For instance, a web server service might require the network service to be started before it can start itself.

Troubleshooting on Linux Security

Resolving DNS Issues with resolvectl and systemd-resolved in a Home Network

Introduction to DNS Resolution

Understanding systemd-resolved

Troubleshooting Slow Network Connectivity with ss and resolvectl on Linux

Introduction to Network Troubleshooting

Understanding ss

Resolving Dependency Conflicts When Mixing Third-Party Repositories with Distribution Packages

Introduction to Dependency Conflicts

Understanding Dependency Conflicts

Troubleshooting Poor Video Performance on Linux Laptops with Hybrid Graphics and Wayland

Introduction to Troubleshooting

Troubleshooting Common Connection Issues with resolvectl and ss on Linux

Introduction to Troubleshooting Connection Issues

Troubleshooting Disk Usage Issues with Duplicate Files and Unnecessary Logs on Btrfs and Ext4 Filesystems

Introduction to Disk Usage Issues

Rescuing a Linux System Stuck in Emergency Mode: A Step-by-Step Recovery Guide

Introduction to Emergency Mode

Identifying the Issue

Troubleshooting Failed Mounts at Boot Time with systemd and fstab

Introduction to Troubleshooting Failed Mounts

Rescuing a Broken Linux System with a systemd Emergency Mode Shell

Introduction to Emergency Mode

Troubleshooting Slow DNS Lookups with systemd-resolved and resolvectl

Introduction to Troubleshooting Slow DNS Lookups

Understanding systemd-resolved

Troubleshooting Broken Dependencies After Adding a Third-Party Repository

Introduction to Dependency Troubleshooting

Understanding Dependencies

Troubleshooting systemd Service Startup Failures with Dependency Ordering and Journalctl

Introduction to systemd Service Troubleshooting

Understanding systemd Dependencies

Understanding `ss`