Free course

TLS and Certificates Course

Inspect TLS connections, create a local certificate authority, run HTTPS and mutual TLS labs, and diagnose certificate failures with evidence.

5 modules · 25 lessons · No signup

Prerequisites: Shell Commands, Networking Foundations, HTTP and curl

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What you'll learn

Create and protect keys, issue local certificates, serve verified HTTPS and mutual TLS, and identify the exact cause of a failed handshake.

Course contents

  1. Inspect TLS

    Inspect live handshakes, certificates, names, chains, and negotiated connection properties.

    1. ✓ Connect with openssl s_client
    2. ✓ Read a certificate
    3. ✓ Understand the certificate chain
    4. ✓ Record the negotiated connection
    5. ✓ Check your understanding: inspect tls

  2. Build a local certificate authority

    Create protected keys, a local CA, CSRs, and signed leaf certificates for a controlled lab.

    1. ✓ Generate a private key
    2. ✓ Create a local CA certificate
    3. ✓ Create a certificate signing request
    4. ✓ Sign a server certificate
    5. ✓ Check your understanding: build a local certificate authority

  3. Serve local HTTPS

    Run a local HTTPS application, trust the lab root narrowly, and verify names from multiple clients.

    1. ✓ Run a Node.js HTTPS server
    2. ✓ Map the lab hostname
    3. ✓ Trust the lab CA for one command
    4. ✓ Serve a complete chain
    5. ✓ Check your understanding: serve local https

  4. Diagnose TLS failures

    Reproduce hostname, time, chain, protocol, and key failures and identify the exact failed check.

    1. ✓ Diagnose a hostname mismatch
    2. ✓ Diagnose certificate validity time
    3. ✓ Diagnose a missing intermediate
    4. ✓ Diagnose protocol and key failures
    5. ✓ Check your understanding: diagnose tls failures

  5. Mutual TLS and operations

    Require client certificates, convert formats, rotate identities, and complete an evidence-based TLS review.

    1. ✓ Issue a client certificate
    2. ✓ Require client authentication
    3. ✓ Convert certificate formats
    4. ✓ Plan rotation and recovery
    5. ✓ Check your understanding: mutual tls and operations