Free course

DNS Course

Learn how domain names resolve, manage common DNS records, understand delegation and caching, debug failures, and change providers safely.

6 modules · 30 lessons · No signup

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What you'll learn

Configure and inspect a DNS zone, connect a domain to web and email services, trace a lookup, and diagnose stale, missing, or incorrect answers.

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Course contents

  1. How DNS works

    Names, labels, resolvers, root servers, TLDs, authoritative servers, and caches.

    1. ✓ What DNS solves
    2. ✓ Names, labels, and fully qualified names
    3. ✓ Follow a DNS lookup
    4. ✓ Recursive resolvers and caches
    5. ✓ Check your understanding: how DNS works

  2. Zones and delegation

    Registries, registrars, DNS hosts, zones, nameservers, delegation, and authority.

    1. ✓ Registry, registrar, and DNS host
    2. ✓ Zones, the apex, and subdomains
    3. ✓ Nameservers and NS records
    4. ✓ SOA records and authority
    5. ✓ Check your understanding: zones and delegation

  3. DNS record types

    A, AAAA, CNAME, MX, TXT, CAA, SRV, PTR, and the rules that connect them.

    1. ✓ A and AAAA records
    2. ✓ CNAME records and aliases
    3. ✓ MX records and priority
    4. ✓ TXT, CAA, SRV, and PTR records
    5. ✓ Check your understanding: record types

  4. Caching and queries

    TTL, negative answers, dig, traces, and direct authoritative queries.

    1. ✓ TTL and cached answers
    2. ✓ NXDOMAIN, no data, and negative caching
    3. ✓ Query DNS with dig
    4. ✓ Trace resolution and query authority
    5. ✓ Check your understanding: caching and queries

  5. Websites and safe changes

    Connect websites, understand DNS proxies, migrate records, and debug failures.

    1. ✓ Connect a domain to a website
    2. ✓ DNS-only and proxied records
    3. ✓ Change DNS records safely
    4. ✓ Debug a DNS failure
    5. ✓ Check your understanding: websites and changes

  6. Email and DNS security

    SPF, DKIM, DMARC, DNSSEC, encrypted DNS, and a final zone review.

    1. ✓ SPF records
    2. ✓ DKIM and DMARC
    3. ✓ What DNSSEC protects
    4. ✓ Encrypted DNS and a final zone review
    5. ✓ Check your understanding: email and DNS security