 Welcome to this course. I am Anna Sparopto, a system professor in network security at the University of Tanda, and I will be your main lecture for this module on Internet Security, Attack and Defense. This module has been developed by a team of researchers at the University of Tanda, and it is part of the Internet Security course. This module focuses on attack defense techniques, as we see them in use in network nowadays. If you are interested in security protocols and web hacking, you might want to follow also the other modules of this MOOC. Each lecture in this module has three main ingredients. The first is attacks. In our lecture, we will cover a selection of attacks that we encounter in current networks. The second ingredient is defense. We will introduce and reason about defense and mitigation techniques that can be applied to real attacks. The last ingredient is measurements. Network measurements is the approach we will take in this course to observe and characterize attacks. This means that we will give example of real attacks that have been measured in production networks. Also, you will familiarize yourself with real network traces and learn how to analyze them. After this course, you will be able to understand, work with and apply concepts in the field of attacks, defense, and measurements. In particular, you will be able to describe the enabling mechanism of current attacks and discuss possible countermeasure. We will also acquire practical experience in our attacks work and how you can characterize them. Finally, you will be able to design possible defense strategy based on the countermeasure you will see in the course. The module is organized as follows. After the introductory week, we will have seven weeks of lectures. We will start with an introduction to network measurements with the goal of providing an overview of the topic and familiarizing you with trace analysis. After that, we will dive into a set of attacks. First, we will present an overview of attacks such as scans, worms, and botnets. Then, in week four and five, we will talk about denial of service attacks and DNS security. In weeks six and seven, we will focus on defense by looking at intrusion detection, firewalls, and nets. Finally, we will conclude this course with a lecture on advanced persistent ref. In this overview, we have highlighted the main focus of the lecture, that is either attack, defense, or measurements. In truth, each lecture contains elements of each of these three ingredients. So you can expect to hear about example of measured attacks and mitigation measures in several places in this module. Each lecture provides the following material. In the video lectures, you can find the relevant information about the topic of the lecture. These videos are a good starting point into the topic, but they are not exhaustive percent. We always encourage our students to deepen their knowledge with additional material, which we will propose as self-study. Each lecture, we also propose a set of quizzes that will help you to memorize important concepts. Finally, each week, with the exception of this first lecture, we'll have a homework and its own exercise to be handed in before the next lecture.