Dns 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 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.

Taming systemd-resolved: Troubleshooting DNS leaks and resolving domain name surprises on Linux desktops and servers

Fri, 05 Jun 2026 10:35:34 +0200

Introduction to systemd-resolved

I’ve seen systemd-resolved become a crucial part of many Linux distributions, including Ubuntu, Debian, and Fedora, as of 2026. It’s designed to provide a robust and secure way to resolve domain names on Linux systems. However, like any complex system, it can sometimes behave unexpectedly, leading to DNS leaks and domain name resolution surprises.

Understanding DNS Leaks

A DNS leak occurs when your system sends DNS queries to an unintended DNS server, potentially revealing your browsing history and online activities to third parties. This can happen when your system is configured to use a specific DNS server, but systemd-resolved is not properly configured to respect this setting. Don’t bother with manually trying to diagnose DNS leaks - just use online tools such as dnsleaktest.com or ipleak.net to check for them.

Taming systemd-resolved: How to Configure DNS Settings for Split Horizon Environments

Thu, 04 Jun 2026 11:14:28 +0200

Introduction to systemd-resolved

I’ve seen many Linux admins struggle with configuring DNS settings for split horizon environments. systemd-resolved, a DNS resolver component of the systemd suite, can make life easier. In this article, I’ll walk you through how to configure DNS settings for split horizon environments using systemd-resolved.

Understanding Split Horizon Environments

Split horizon environments are network setups where multiple DNS servers provide different answers for the same domain name, depending on the client’s location or network. I’ve encountered this in organizations with multiple offices or data centers, where different DNS servers serve different locations. For example, a company with offices in the US and Europe might have two separate DNS servers, one for each region, providing different IP addresses for the same domain name.

Troubleshooting DNS Leaks with systemd-resolved and resolv.conf on a Small Linux Server

Fri, 29 May 2026 08:36:48 +0200

Introduction to DNS Leaks

I’ve seen DNS leaks cause issues on even the most secure Linux servers. Ensuring your DNS setup is solid is crucial, and one common problem is a DNS leak, where your system inadvertently reveals your DNS queries to unauthorized parties. In this article, I’ll walk you through troubleshooting DNS leaks using systemd-resolved and resolv.conf on a Linux server.

Understanding systemd-resolved

systemd-resolved is a powerful tool that provides DNS resolution capabilities. It’s designed to be a caching, validating DNS resolver that can also handle DNSSEC validation. To check if systemd-resolved is running on your system, use the following command:

Taming Split DNS Chaos with systemd-resolved and Local Hostname Resolution

Wed, 27 May 2026 08:34:11 +0200

Introduction to Split DNS Chaos

I’ve seen this go wrong when working with multiple networks or self-hosted services: split DNS configurations can become a real headache. Luckily, many Linux distributions have started adopting systemd-resolved as the default DNS resolver, which makes managing split DNS scenarios much simpler. In this article, I’ll walk you through how to use systemd-resolved for local hostname resolution and taming that split DNS chaos.

Understanding systemd-resolved

The real trick is understanding how systemd-resolved works. It’s a systemd component that provides DNS resolution and caching, and it can be configured to use multiple DNS servers and handle split DNS scenarios with ease. To check if systemd-resolved is enabled on your system, run the following command:

Taming systemd-resolved: Avoiding DNS Leaks and Surprises with Split DNS Configurations

Sun, 24 May 2026 10:21:18 +0200

Introduction to systemd-resolved

I’ve worked with Linux systems for years, and one thing that’s become increasingly important is DNS resolution. systemd-resolved is a DNS resolver component of the systemd suite, designed to provide a flexible and secure way to resolve domain names. It was introduced in systemd version 216, released in 2015, and has since become a standard component in many Linux distributions. By default, systemd-resolved uses a split DNS configuration, which can sometimes lead to DNS leaks and unexpected behavior. I’ve seen this go wrong when a system has multiple network interfaces or connections, each with its own DNS resolver configuration.

Taming systemd-resolved: Tips for Troubleshooting and Customizing DNS Resolution on Linux

Fri, 22 May 2026 10:04:50 +0200

Introduction to systemd-resolved

I’ve been using systemd-resolved for a while now, and I have to say, it’s a big improvement over traditional DNS resolvers. As of 2026, many Linux distributions, including Ubuntu, Debian, and Fedora, have adopted systemd-resolved as the default DNS resolver. While it offers several benefits, including improved security and performance, some users may encounter issues or require customization to suit their specific needs. Don’t bother with trying to disable it, though - it’s usually worth the effort to get it working right.