DEV Community: Alexandros Kourtis

What is DNS and how does it work?

Alexandros Kourtis — Tue, 21 Feb 2023 07:09:24 +0000

What is DNS and how does it work?

Basic description

DNS, which stands for Domain Name System, is a system that translates human-readable domain names, such as example.com, into IP addresses, which are used by computers to identify each other on the Internet.

The DNS system is composed of several components, including:

DNS clients: These are typically your internet-connected devices, such as your computer, phone, or tablet. When you enter a URL into your browser, it sends a DNS query to the nearest DNS resolver.
DNS resolvers: These are servers that are responsible for looking up IP addresses for domain names. Your ISP or another provider typically provides the DNS resolver. It caches frequently accessed IP addresses, so the queries are resolved more quickly, which saves time and reduces network traffic.
Root servers: These are the core of the DNS system, and they maintain a database of top-level domain (TLD) servers. They are responsible for handling requests for TLD servers.
TLD servers: These servers are responsible for resolving queries for domain names with specific top-level domains, such as .com, .net, or .org.
Authoritative servers: These servers are responsible for holding the IP addresses for domain names.

Detailed functionality

When you type a domain name into your web browser, the browser sends a DNS query to the nearest DNS resolver, which then forwards the request to the root server. The root server responds with the location of the TLD server for the top-level domain of the requested domain name.
The DNS resolver then contacts the TLD server and requests the IP address for the requested domain name. The TLD server responds with the location of the authoritative server responsible for the requested domain name.
The DNS resolver then contacts the authoritative server and requests the IP address for the requested domain name. If the authoritative server has the IP address in its database, it responds with the IP address, which the DNS resolver then returns to the DNS client.
Finally, the DNS client uses the IP address to establish a connection with the web server that hosts the requested website, and the website is loaded in the browser.

Find more here:

https://en.wikipedia.org/wiki/Domain_Name_System

And here:

https://www.webnic.cc/what-is-a-domain-name-server-dns-and-how-it-works/

What is the HTTP protocol? Explained simply for noob web developers 😁

Alexandros Kourtis — Mon, 23 Jan 2023 12:57:22 +0000

The HTTP Protocol 🤔

It stands for Hypertext Transfer Protocol (HTTP) and it's the system that enables the transferring of data on the internet. A client, e.g. browser, connects to a web server that hosts the resources. Resources are documents such as HTML and PDF files that are identifiable by a unique identifier (URL).

The HTTP protocol is a two-way communication protocol that sets up the client to make a Request and wait for the server to Respond.

What are the most common Request Methods?

GET: the retrieving of information from a specified resource.

POST: sends a request to the specified resource.

PUT: changes the resource's representation with the payload.

DELETE: This command deletes the given resource.

HTTP Messages consist of a Header & a Body

A header and body comprise the content of a request and response.

The header contains the necessary information about the request or response. Additional information might be supplied in the header to modify the request's processing.

The body of an HTTP message is optional, although it is the vehicle that transports the requested data (text, files, images, etc), also called payload.

Status Codes for HTTP

When a request is delivered to the web server, the web server responds with a response. A response will contain a status code as well as headers. The status code is a three-digit integer that indicates the outcome of the request. The status codes are listed below.

HTTP Protocol is Stateless

The HTTP protocol is stateless, which means that each transaction (request and response) is independent of the others. There may be use cases where state is necessary, where cookies and sessions are two methods through which a web application can preserve state.

Original:
https://dccyberclub.com/html/article.html?titleslug=what-is-the-http-protocol-explained-simply-for-noob-web-developers--

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