UCW (Uncomplicated Firewall) is an easy-to-use netfilter firewall management program. It uses a command line interface that consists of a few simple commands and uses iptables for configuration, so it is the frontend of iptables. In this description we will look at the installation and basic use and configuration of the UFW firewall, the steps of which I will perform on a minimal Debian 11 server.

If you frequently use virtual machines with VirtualBox, it is a more convenient and time-saving solution if you do not create and configure a new virtual machine for each installation, but use the existing ones. In some cases, this can cause problems, such as when you try to start your installer in EFI mode, but it does not want to start. In this short little troubleshooter, we will look at how to start ISO installers on EFI mode virtual machines.

VirtualBox allows you to run virtual machines on your computer that share the computer's hardware resources with the host operating system. VirtualBox also provides the ability to use dynamically growing storage, which allows you to create drives that are (virtually) the same fixed size inside, but the physical image files themselves are only a few megabytes in size when created and grow depending on the amount of data loaded. This is unfortunately not true backwards, so if you delete something from the virtual machine, for example, the size of the physical image file on the virtual storage device will unfortunately not be reduced. In this description, we will look at how to manually shrink the dynamically growing image files of our VirtualBox virtual machines to the size actually used on Linux and Windows systems.

If you use the command line frequently and have to work in several windows at once, it is essential to have a multi-tab terminal application that is comfortable to use and has the right knowledge. In this small user tutorial, you will learn about the Asbrú Connection Manager Linux application and its basic functions. On this page, we will install the program and review the global settings.

With the help of LAMP systems, we can run dynamic web pages on our server or even on our home computer. I have previously built LAMP servers for Debian 8 (Jessie), Debian 9 (Stretch) and Ubuntu 18.04 LTS (Bionic Beaver), and in this description we will install the LAMP server components for the Ubuntu 20.04 LTS (Focal Fossa) Linux distribution.

ImageMagick is a free and open source, cross-platform software package designed primarily for displaying, creating, converting, modifying, and editing raster images, but can also handle a variety of vector formats such as EPS (Encapsulated PostScript), AI (Adobe Illustrator) , PDF (Portable Document Format), etc. In total, it supports more than 200 image file formats. And Imagick is a native PHP extension that allows you to manage different image formats in a web environment using the ImageMagick API. In this quick troubleshooter, we take a look at how to fix errors from the software security policy with a little intervention.