The main tool to set up the firewall on Ubuntu is iptables. It is powerful, but very complicated to learn. Fortunately, there is an alternative called UFW (for Uncomplicated FireWall), that is described by Ubuntu as “a frontend for iptables”. Basically, UFW lets you set rules for your firewall in a much easier way that iptables does. Let’s learn how to set some basic rules using UFW!
In this series of tutorials we’ll take a look at basic server security, and in this first article we’ll learn how to improve SSH security. Any machine connected to the Internet immediately becomes a potential target to any kind of attack (hackers, automatic bots, …). Security is somewhat less of a concern for regular Web hosting (shared hosting or managed hosting for example), as most of it is managed by your hosting provider. Servers that you fully manage, however, come with absolutely no security out of the box. This is the case for most dedicated servers, VPS (Virtual Private Servers) and Cloud platforms (AWS, Google Cloud, …).
In some situations, it can be useful to simulate user events on a keyboard or mouse, without an actual keyboard or mouse. The original idea that made me look into this subject, was that I wanted to run RetroPie on my Raspberry Pi with different ways to control the system. Instead of a keyboard, I wanted to use GPIO inputs (buttons or joysticks), or even a web interface that I could access from my phone. We’ll use a program called xdotool to do this.
The Raspberry Pi is a small single board computer that was originally intended for education and developing countries. In the last 5 years, it achieved way more than this, as it is now one of the best and easiest platforms for tinkerers and DIYers. It is basically a full Linux computer with a small form factor and energy consumption, making it ideal for homemade projects. Most of the time, you can use the Raspberry Pi as a headless machine, without a monitor, keyboard or mouse, and just use Telnet or SSH to access it. This considerably reduces the total cost of a project, as there will be no need to buy a screen, keyboard or mouse. However, the tricky part of this setup is the first installation of the OS. In this tutorial we’ll learn how to set up a Raspberry Pi in a fully headless way.