The DNS course for developers

Never be confused about DNS again.

Hi! I'm Ruurtjan Pul, a full-stack developer who used to suck at DNS.

I've had many side projects over the years, and never completely understood why my DNS records didn't update. Or how long to wait until they do. Worse yet, I've had my emails bounce because I misconfigured SPF, DKIM and DMARC.

I decided to learn DNS by making Nslookup.io, a web interface for DNS. I've read the RFCs to implement a custom DNS client and I now run my own DNS server. Nslookup has become popular enough to replace my income, so I'm working on it full-time since early 2022.

Now that I've spent so much time learning DNS, I'm sharing everything I've learned in this comprehensive video course. It will teach you to reason about DNS from first principles and guard you against the mistakes I made. When you finish this course, you will be able to manage and debug DNS with confidence.

Learn DNS once and for all.

They say you should learn the fundamentals, and the rest will fall into place. DNS is right at the foundation of the internet. Having a clear understanding of DNS will help you configure and debug DNS many times throughout your career.

DNS hasn't changed that much since its introduction in 1983 and it's unlikely to start now. DNS isn't going anywhere. The earlier you learn DNS, the longer you'll benefit.

The great thing about DNS is that all the information is public. You can have perfect clarity if you know where to look.

Who is this course for?

This course is for you if you want to gain mastery over DNS.

It assumes you have a basic understanding of how the internet works, but you don't need to be an expert. This course assumes no prior networking experience and involves no programming.

If you've worked on DNS full-time for over a year, this course is probably not for you. Otherwise, you'll learn a lot! If you invest in your knowledge today, you'll benefit for the rest of your career.