Security

Introduction to systemd-resolved

I’ve spent years working with Linux, and one component that’s given me trouble is systemd-resolved, the DNS resolver service that comes bundled with systemd. Recently, I noticed my DNS queries were leaking, and I was getting annoying resolver errors on my Linux desktop. This prompted me to dive deeper into systemd-resolved and figure out how to tame it. I’ve seen this go wrong when people don’t take the time to understand how it works, so let’s start with the basics.

Introduction to Log Rotation

I’ve seen log rotation become a major issue on small servers with high IO workloads - it’s a problem that can sneak up on you quickly. Logs can grow at an alarming rate, and if you don’t manage them properly, they can fill up your disk space in no time. The real trick is to stay on top of log rotation, and that’s where tools like logrotate come in.

Firewalls are essential for securing your Linux system from unauthorized access and potential attacks. Among the various tools available, firewalld is a powerful yet user-friendly firewall management solution designed to make configuring and managing firewalls simpler. This guide introduces firewalld and its companion tool, firewall-cmd, breaking down their features and basic usage.

What is Firewalld?

firewalld is a dynamic firewall management tool that provides a way to configure firewall rules without disrupting active connections. It’s widely used on modern Linux distributions like Fedora, Red Hat Enterprise Linux, AlmaLinux, and CentOS.

In the world of networking, understanding how data flows across a network is critical for troubleshooting, security, and performance optimization. One of the most powerful tools at a network professional’s disposal is tcpdump. This command-line packet analyzer allows users to capture, filter, and dissect network traffic in real time, offering unmatched insights into what is happening on the wire.

Learn more about tcpdump on its official website, where you can find documentation, examples, and updates.