sebastian@madej:~$ whoami
Blue team, networking and systems administration. I build infrastructure and make sure it stays secure — from cabling in the ground to the SIEM.
My home network is my training ground. I monitor it, scan it for holes and keep expanding it — every new device is one more thing to secure.
Collecting logs and alerts from several machines and detecting suspicious events.
Regular vulnerability scans of the whole network and patching whatever turns up.
Managed hardware, subnetting, isolating services and IoT devices.
Virtual machines for testing distributions and services, container management.
A dashboard showing CVEs and data leaks, plus automations for the household.
Microcontrollers, servos, LED control and small IoT projects.
Rigging stages, sound, lighting and LED screens for stadium concerts at PGE Narodowy and Tauron Arena. Cabling, health and safety, working under time pressure in a large crew.
React frontend integrated with a REST API written in .NET 6.
Diagnosing and servicing computers: disassembly, cleaning, soldering components, helping repair a server.
Recruitment task: an order system built on an event queue with Spring Boot and Kafka.
A tool that checks what a search engine reveals about my own domains: files, admin panels, forgotten pages.
A server network behind a Velocity proxy, a custom damage system for an RPG server using Redis to handle more players, and a shop system with a Spring Boot backend. This is where I learned to design systems from scratch.
Breaking security isn't what drives me. Making sure nobody breaks mine is.
It started when I was 8: my cousin set up a Minecraft server and I watched him write his own game mechanics. Soon I had my own server and weapons that had no right to exist in vanilla Minecraft. That's where I learned that every big problem can be broken down into small steps.
Then came Java plugins, my first Redis to handle more traffic, and my first own server, bought while I was still in technical school — an old Z400 with 12 GB of RAM. That's when I noticed I enjoyed running the whole infrastructure and its users more than playing.
Today, after an IT technical school and now studying cybersecurity, I keep expanding my home network, which I monitor and scan continuously. After hours I tinker with ESP32s, try out new Linux distributions, and pick up electrical skills from my dad, an electrician: circuits, power, building cabinets.
Polish state vocational qualification: administration and operation of computer systems — servers, local networks, computers and peripherals.
Polish state vocational qualification: building and administering websites, web applications and databases — HTML, CSS, JavaScript, PHP, SQL.
OSI and TCP/IP models, IPv4/IPv6 addressing, configuring routers and switches in Cisco IOS.
IT technician (technical secondary school)
Computer science, cybersecurity specialisation, engineering degree