Networking & HTTP·Networking from DNS to production

TLS

Understand certificates, handshakes and the padlock.

Beginner 13 min read Lesson 6 of 300 Challenge included

What you will be able to do

Certificates bind a hostname to a public key.
TLS 1.2 and 1.3 are acceptable; older versions are not.
Use HSTS after HTTPS works everywhere.
Renew certificates automatically.

In plain English

TLS provides encryption, integrity and authentication. The client verifies the server certificate against a trusted authority and checks the hostname. Modern TLS 1.3 shortens the handshake. HSTS tells browsers to use HTTPS only.

terminalTerminal

curl -vI https://www.edubyte.tech/ 2>&1 | grep -E 'TLS|subject|issuer|expire'
openssl s_client -connect www.edubyte.tech:443 -servername www.edubyte.tech </dev/null 2>/dev/null | openssl x509 -noout -dates

Your turn

Inspect certificate dates

Medium

Use openssl to print the notBefore and notAfter dates for a host.

BASH · starter

openssl s_client

Check your understanding before moving on.

Knowledge checkQuestion 1

What does a TLS certificate bind together?

Select an answer to continue

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Next: Debugging requests

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