Preface
Anouar Adlani on why he wrote this course, his path through internet infrastructure, and who this is for.
Preface
I came to DNS the way most engineers do: because something broke.
In 2006, I joined EuroDNS as a software architect. It was a small registrar operating in Luxembourg, building infrastructure for domain registrations in European markets. I thought I'd be working on web applications. Within six months, I was deep in DNS zone management, registry protocols, WHOIS systems, and the plumbing that makes domain names work. I didn't plan it. The infrastructure needed someone who could build on top of it, and I was available.
I stayed for nine years. By the end, I was CTO. In that time, we built and ran the systems that process millions of domain operations — registrations, transfers, renewals, DNS record updates. I saw DNS from the inside of a registrar: the failure modes, the edge cases, the ccTLD quirks that make every large migration interesting, the gap between what the RFC says should happen and what actually happens when 47 domains need to transfer and two of them have expired auth codes.
After EuroDNS, I moved to EBRAND, where I built X-RAY — a platform that monitors the domain namespace for threats at scale. That's a different perspective. Instead of operating DNS infrastructure, I was watching what people do with domain names: typosquatting, phishing campaigns, brand impersonation, domain hijacking. The same infrastructure I'd spent years building was also the attack surface for a whole category of threats that most organizations weren't equipped to detect.
Those two experiences — inside the registrar infrastructure, then watching the threat landscape from outside — are where this course comes from.
Who This Is For
Three kinds of people.
Developers who keep getting surprised by DNS. You know what an A record is. You've set up domains before. But every time something breaks — email stops delivering, a deployment fails because of a resolver issue, a TLS certificate doesn't provision — you're spending hours figuring out why. You want a mental model solid enough that DNS problems don't feel like random acts of infrastructure.
Ops and SRE engineers who want to own their DNS infrastructure rather than just manage it reactively. You're the person who gets paged when DNS breaks. You want the depth to know whether a problem is in the authoritative server, the resolver, the application, or somewhere else in the chain.
Domain managers and brand protection professionals who want a framework for decisions, not just a list of what to register. You're responsible for a portfolio, a brand, an exposure to the domain namespace. You need to think systematically about what to own, what to monitor, and when UDRP is the right tool.
This course doesn't require any of those roles as a prerequisite. It builds from the fundamentals — what DNS actually is, how resolution works, what the record types do — and moves through security, developer patterns, reliability, email authentication, advanced concepts, and portfolio strategy. By the end, you have a complete picture, not a set of isolated pieces.
What You'll Get From It
A working mental model of DNS that applies across all the places you encounter it.
Specific: the ability to dig your way through a DNS problem and understand what you're seeing. The vocabulary to describe failure modes clearly. The judgment to know when a problem is a DNS problem versus an application problem versus a registrar problem.
Less specific but more durable: the habit of treating DNS as infrastructure. Setting it up correctly from the start. Monitoring it. Including it in change management processes. Not getting surprised by it in production.
The course exists because I spent years watching smart engineers get caught off guard by DNS — not because they were careless, but because nobody had given them the complete picture. Most DNS documentation is either too narrow (a reference for one record type) or too broad (a textbook on the full protocol stack). The working professional's perspective — here's what you need, here's why it matters, here's what breaks if you get it wrong — is less common.
That's what I tried to write.
Anouar Adlani