Why this is free

I am Jesus Perez Duerto. This page is first person because you should know who is talking before you take the path.

The story behind why it is free

I still remember being about seven when my mom decided to get a computer at home. She managed a bank branch, and the IT guy there offered to build a “clone,” which in those days meant buying parts and assembling them into a basic machine rather than buying a brand-name box. One day he came over to put it together. I asked how he could take all those loose pieces and make something that actually worked. I got so curious it felt physical. It felt like a challenge I had just accepted without saying so out loud: someday I would build my own computers.

My first operating system was Windows 95. Curiosity did not stop at the case. I started by taking machines apart at the hardware level, then I moved into the software, chasing the same question from a different angle. I wanted to understand how everything worked, not just how to use it, and I spent a lot of time learning in the slow way, by opening things and putting them back together. Then the internet arrived, and it really was a whole new world. I still remember dialing in on a basic modem, that scratchy handshake, and fighting with my family for the phone line so I could stay connected a little longer.

At first, computers were about making them faster so I could play games. Piece by piece I upgraded whatever I could afford or scavenge. My first graphics card was a 3dfx Voodoo, the kind of card people argued about in forums until the company went bankrupt and was bought by NVIDIA. I was obsessed with benchmarks. I would squeeze every point out of those machines, tweak something, run the score again, and feel like I had stolen a little more performance from the hardware. For a long time that was my world: games, tweaking the OS, exploring the internet. I never got into programming or hacking then. I just did not have the motivation yet. The hunger was there for systems, but not yet for breaking them or writing them.

That changed in college, studying telecommunications engineering. Friends were doing all kinds of weird things online: selling stuff, building bots that fired ads, running sites that somehow stayed up. I got curious about the internet in a different way and started reading Kevin Mitnick. Before long I knew the jargon, I was learning networks for real, and I was poking around with Linux. Bit by bit I shifted from gaming to hacking and exploring networks. Fyodor’s Nmap book opened another door. Suddenly scanning was not a parlor trick. It was a map. I took Cisco CCNA training and learned enough about how networks really work to do wild things with that map in hand. I spent stretches of time just scanning and discovering open ports on the internet, poking around, finding thousands of machines still sitting on default passwords. That is when I understood that most companies had no clue about security. Not in a dramatic movie way. In a quiet, everywhere way.

I was lucky after graduation. Venezuela was pushing government systems toward UNIX, and the timing put me in the middle of that shift. I took every training I could on setting up UNIX systems and servers. With that plus the network knowledge, my first pentest was almost unsurprising. It felt easy in the way that years of quiet preparation sometimes feel easy when the moment finally arrives. I still remember being sent into a company to hack their systems. My boss was not sure I could pull it off. Same day I had compromised the domain and had screenshots from the CEO’s laptop. That feeling stuck. I was addicted to cybersecurity books. I would buy them and devour them in days, chasing the next technique the way I used to chase the next benchmark score.

My career took turns after that. Managing teams. Climbing the corporate ladder. Learning how to lead and motivate people. Those skills matter, and I worked hard at them, but my heart stayed in this technical world that still feels half unexplored. A lot has changed since the clone PC and the modem wars. Computer intelligence will make things completely different. I have played with AI for years and watched it evolve from a curiosity into something that reshapes how we work. Soon AI agents may be much smarter than we are. Curiosity, the drive to test things, and clever ideas will still be ours. What changes is the tools. They will let us explore those ideas with ease. These are exciting times, if you keep your hands on the craft.

I wanted this material free for anyone. If you are just starting, it is worth learning the past and understanding how things work as deeply as you can, so you can see the evolution instead of only the latest fashion. History matters here. You will not understand everything. There is too much. But a high-level map of how it all fits will take you a long way. Enjoy this. My only hope is that it makes you excited to keep learning.

I work in English and Spanish. I stay technically close enough to challenge assumptions. I keep teaching.

Why there is no invoice

I already taught. CCNA in Caracas. A hacking classroom in Boston. People showed up because they wanted the skill, and I liked the moment when a concept clicked harder than I liked the enrollment form.

This site is that instinct without a tuition wall. I am not selling you a badge. I am not mirroring someone else’s academy. I am writing the concepts I wish a sharp beginner had in one place: how a computer works, how a network tells the truth, how you find, how you get in, how you rise, how identity actually works, and how you write it down so a defender can fix it.

The walkthrough notes on this domain can provide optional examples after you understand the underlying concepts. You can also learn entirely through the free lessons, diagrams, questions, and in-page models. An external lab is optional and may have its own account, access, or payment requirements. A machine’s retired status or a published walkthrough does not grant permission: the owner or provider defines the allowed systems and activity.

AI, without the sermon

Use a language model. I do. It is good at drafting a command, restating a man page, and reminding you of a flag you have typed a hundred times. Today I also apply automation and AI to real security problems at work, as a responsible sensor and a typist, not as an unsupervised operator.

A language model learns patterns from training data and uses context to generate responses. It can explain ideas, compare alternatives, and help reason through a problem, but fluent wording does not establish accuracy. It may produce an incorrect detail or a reference that does not support its claim. Ask for the reasoning, compare it with reliable sources, and keep uncertainty visible.

Use the model to support understanding: request a simpler explanation, predict what a fictional example means, or compare two defensive designs. Before applying a suggestion to any system, understand its effect and verify both the relevant facts and permission. It is fine to pause, ask basic questions, and revise your first answer.

How to read the rest

Open the learning map and choose a route that suits you. History offers context; foundations explain the building blocks. You can follow them in order or use the suggested prerequisites when a later topic interests you. Security in Depth offers short lessons to explore a concept further, and the gym gives you free in-page activities to put those ideas into practice.

The Spanish path lives under /es/hack-and-learn/. I write both. I am not going to machine-translate twenty modules and pretend they have a voice.

You are welcome here whether you want safer everyday habits, an introduction to a new field, or deeper technical understanding. A few minutes with one concept is a worthwhile session. You do not need to collect flags or finish every track to benefit.

What you can now say

You now know the teacher’s motivation, how to choose a manageable route, and how to use assistance while checking evidence. Start with the learning map, or revisit a foundation whenever a term is unfamiliar.