About SubnetMaster
SubnetMaster is a personal project I created to make computer networking clear, practical, and approachable for anyone. My goal is to provide the resources I missed while learning, because concepts such as IP addressing, masks, CIDR, FLSM, and VLSM are often explained in unnecessarily difficult language. Here I try to make everything understandable through examples, tools, and downloadable resources that help you validate what you are learning. Most resources are free and accessible without registration.
What is SubnetMaster and who is it for?
SubnetMaster originally began as a project I built for a first-year programming course in the Spanish ASIR systems-administration program several years ago. It now aims to be a useful resource for anyone interested in computer networks and subnetting.
This website is intended for:
- Networking students (ASIR, courses, technical training, etc.).
- Self-learners who want to learn networking from scratch.
- IT professionals who need to refresh subnetting or prepare for exams and interviews.
- Anyone who wants to understand the “why” behind the calculations, not just the result.
Learning path
Topic hubs that let you progress step by step without losing context.
Clear explanations
Complex concepts explained with examples and straightforward language.
Practical tools
Calculators and networking tools to validate results and learn faster.
Exercise bank
Exercises for practicing subnet calculations by hand and checking the results.
Why does this project exist?
A couple of years ago, while I was studying ASIR, I was taking IPE (a Spanish employment-pathway subject) and trying to find an up-to-date payroll calculator that had exactly what I needed. At the same time, our Programming course required us to build an app in HTML, CSS, and JavaScript, so I decided to build my own payroll calculator with the design and features I wanted.
I still needed to use it from anywhere, so I hosted it on a free domain (calcnomina.neocities.org) and soon afterward added notes about the subject, employment law, and job searching. The goal was to make it useful both for my classmates and for my own studies.
SubnetMaster is an independent project focused exclusively on networking and subnetting.
Soon afterward, when our Networking course reached subnetting, I ran into the same problem: I could never find a tool or website that truly helped me learn. I decided to build my own FLSM and VLSM subnet calculators and host them on a free domain so they would always be available (subnetmaster.neocities.org) and share them with classmates whom I often helped with resources and explanations.
SubnetMaster also grew out of my class notes. It now aims to bring together the resources, notes, and tools I collected throughout my networking training.
A year after creating the project, I realized that many people had used my tools and visited my resources. I decided to maintain the project and expand the number of tools, and over time this also led toespanalaboral.esandsubnetmaster.es.
Who is behind SubnetMaster?
Behind SubnetMaster is a former audiovisual communications professional who spent several years working as a lighting technician, photographer, and web designer before having a workplace accident. That experience made me realize how much time I had already spent working with networks in the audiovisual industry and that my real passion was the Internet.
So I decided to focus on my other passion: computing, the Internet, and the web.
I currently work freelance through my own Web Design and SEO agency in Málaga:aimv Studio. I also work as a freelance systems administrator while preparing for public-sector exams.
How SubnetMaster is organized
The website is organized into main sections (hubs) so you always know where you are and can move quickly between theory, practice, and resources.
Education
A general path with access to guides, resources, and materials for step-by-step learning.
Academy
More structured content: exercises, lessons, and guided learning (in development).
Tools
Calculators (FLSM/VLSM) and utilities for validating results and practicing.
Blog
Editorial posts: project updates, practical cases, and study notes.
Project principles
Clarity above all
I explain concepts using direct language, examples, and clear steps. Less fluff, more understanding.
Practical learning
The tools and examples are there to practice, validate, and correct mistakes.
Original content
The content is written and structured from scratch with a genuine educational purpose.
An evolving project
SubnetMaster is updated progressively with guides, UX improvements, and new tools.
Project status
Last updated: January 2026.
Next planned update: interactive subnetting exercises (February 2026).
The contact page includes a form for sending any message. You can also write directly tohelp@subnetmaster.es.