WebsitesModule 1: The web, explainedLesson 2 of 15
Course progress7%
15 min lesson · Updated August 2026
How does a website reach your screen?
When you open a web address, the browser resolves the domain through DNS, connects securely to a server, sends an HTTP request, receives resources and turns them into the page you see.
What you will learn
By the end, you will understand:
Follow domain, DNS, server and browser roles
Understand request, response, status and HTTPS concepts
Recognize caching and delivery layers without treating them as magic
Visual explainer
See the idea clearly.
A typed URL moves from browser to DNS, secure server connection, HTTP request and response, then HTML, CSS, JavaScript and images assemble on screen.
The journey begins with a URL
01
Read scheme/domain/path
02
Check browser/cache
03
Resolve domain through DNS
04
Connect to server address
05
Negotiate secure HTTPS
06
Send HTTP request
07
Receive status/headers/body
08
Request linked resources
09
Render and run allowed behavior
DNS is a directory system
People remember domain names; networks route using addresses. DNS records help the browser find the service responsible for the domain.
DNS changes can take time to be observed because resolvers cache records. A domain registration and hosting account are different things.
The server answers requests
Response
Meaning
200
The requested resource was successfully returned.
301/308
A permanent redirect points to another address.
302/307
A temporary redirect.
404
The resource was not found.
500 family
The server could not complete the request normally.
HTTPS protects transport
HTTPS uses TLS to authenticate the server connection and encrypt data in transit. It helps prevent nearby parties from reading or altering requests.
HTTPS does not prove the business is honest, the page has no malicious code or stored data is secure. Certificate warnings must not be ignored.
Browsers build the result
HTML describes content/structure, CSS controls presentation and JavaScript can add behavior. The browser fetches these and other resources, creates internal models and paints pixels.
Different browsers and devices can expose implementation assumptions, so testing should not rely on one screen.
Caches and CDNs change the route
Caches reuse stored responses to reduce time and server work. A content delivery network can serve copies closer to users and absorb traffic.
Caching must be configured so private or newly changed content is not incorrectly reused. Purging a CDN does not always clear every browser cache.
Real-world example
Example: a domain works but one page does not
Example
DNS resolves and the server answers, so the home page loads. A product link requests an old path and receives 404. The problem is not “the internet”; it is the missing resource or redirect at that URL.
Try this
Read an address and response
Open browser developer tools for a public page. Identify scheme, domain and path; reload, find the main document request and record its status, content type and whether it came from cache.
Common questions
Questions beginners ask.
What is DNS?
The distributed naming system that helps map domains and service records to network destinations.
What is hosting?
Computing/storage infrastructure that serves website resources and applications.
What is a server?
Software and hardware that receive requests and return resources or results.
What is HTTP?
The web protocol used for requests and responses between clients and servers.
What is HTTPS?
HTTP carried over an authenticated encrypted TLS connection.
What is a status code?
A number in an HTTP response indicating the general result of the request.
What is a CDN?
A distributed delivery network that can serve cached resources closer to users and provide other traffic controls.
Why can a site work for one person but not another?
DNS/cache, location, device, browser, network, consent, account state or staged deployment can differ.
