Module
Module 2 of 6Lesson 2 of 2~14 min

Finding the server and securing the connection (DNS and HTTPS)

Lesson 2 of the module "From address to page" in the course "Explain how a web product works, from browser to server".

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Lesson objective

By the end of this lesson, you will be able to explain how a domain name is translated into an IP address, read the main DNS records and the effect of their TTL, and say what an HTTPS connection guarantees, and what it does not.

Where it fits

From address to page

What happens between the moment you type an address and the moment the page appears?

Lessons in this module

  1. A request's journey, in six steps
  2. Finding the server and securing the connection (DNS and HTTPS) (this lesson)

What you will learn in the course

This lesson is part of the course Explain how a web product works, from browser to server

  • Describe the steps of a web request, from the typed address to the displayed page (URL, DNS resolution, encrypted connection, HTTP request and response, browser rendering).
  • Read an HTTP exchange in the browser's Network tab (method, URL, status code, headers, cookies, duration) and draw a first diagnosis from it.
  • Explain how responsibilities are split between browser, frontend, backend, API, database and third-party services, and place where a business rule must run.
  • Explain the role of a CDN and of caches (browser, CDN, server) and anticipate their effects on speed, data freshness and releases.
  • Tell apart local, preview, staging and production environments, and say what changes from one to another (configuration, data, secrets).
  • Place a symptom (slowness, blank page, error, stale data) in the right layer and ask the technical team precise questions.
  • Produce the annotated diagram of a request's journey through your own product and have it validated by a developer.

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