Book 1

Domains & DNS

From domain names to live websites — how the internet finds you

Free · Digital Textbook

Domain names, DNS records, email authentication, and hands-on troubleshooting.

  • 10 chapters
  • ~4 hours
  • Hands-on exercises in every chapter
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Table of Contents

Chapters

Read in order the first time — later chapters reference the lab company introduced in Chapter 1.

  1. 01 Welcome & How to Use This Book Lab company, exercises, and how the series fits together. 8 min
  2. 02 What Is a Domain Name? Hostnames, TLDs, registrars, domain vs website. 20 min
  3. 03 The DNS Lookup Journey Resolver → root → TLD → authoritative — step by step. 25 min
  4. 04 DNS Record Types A, AAAA, CNAME, MX, TXT, NS with worked examples. 35 min
  5. 05 Registrars, Nameservers & Zones Who controls what — and where to edit records. 22 min
  6. 06 TTL, Caching & Propagation Plan cutovers without surprise downtime. 18 min
  7. 07 Email DNS: MX, SPF, DKIM & DMARC Reliable mail delivery and anti-spoofing. 30 min
  8. 08 Subdomains & Wildcards staging, api, SaaS CNAMEs, wildcard risks. 18 min
  9. 09 Troubleshooting DNS dig, symptom → cause, reusable checklist. 25 min
  10. 10 Capstone: Plan DNS for Workshop Co. Full zone design for a Canadian business. 40 min