Qu'est-ce qu'un domaine ?

14 mai 2024

Within the internet infrastructure, a domain represents a unique name that identifies a website or a set of associated web resources. It is a unique identifier that helps users find a specific website on the internet.

what is a domain

Qu'est-ce qu'un domaine ?

An internet domain refers to a distinct subset of the internet with addresses sharing a common suffix or under the control of a particular organization or individual. It serves as a fundamental component of the internet's hierarchical système de nom de domaine (DNS). Essentially, it's the part of the internet address that comes after the "dot." This part of the domain name system is vital because it helps to organize and categorize different sections of the internet.

Every domain name represents a specific location on the internet and consists of a series of character strings separated by dots. The rightmost label in a domain name, known as the top-level domain (TLD), indicates the most general part of the domain name, often suggesting either the purpose of the entity owning the domain (like .com for commercial entities, .edu for educational institutions) or its geographical context (like .uk for the United Kingdom).

Below the top-level domains in the DNS hierarchy are second-level and potentially lower-level domains, which can be more specific addresses within the higher level domain and often suggest the specific name of a company, product, or service.

By using domain names, the DNS effectively categorizes sections of the internet. This organization makes it easier for users to find websites, while also allowing for scalability and management of internet addresses globally.

Domain vs. Subdomain

A domain and a sous-domaine represent different levels within the hierarchy of the Domain Name System (DNS) of the internet. A domain is a unique identifier made up of a series of character strings (like "example.com"), which serves as the central reference point for an internet presence.

On the other hand, a subdomain functions as a second-level (or lower) partition under the primary domain, intended to organize or differentiate distinct sections of the website without needing to register a new domain name. For instance, “blog.example.com” and “shop.example.com” are subdomains of the “example.com” domain, allowing for the segregation and specialized handling of different content or services while maintaining an overall coherence under the main domain.

Domain vs. Hosting

A domain is essentially the address of your website. It’s a human-readable form of an adresse IP that people use to find your site, like www.example.com. It is managed through the Domain Name System (DNS), which translates domain names into IP addresses that computers use to identify each other on the internet.

Hosting refers to the physical server space where a website's files and data are stored. It involves the infrastructure and services provided by un hôte, which keeps the website accessible on the internet.

In simple terms, if the domain is the address of a house, then hosting is the actual house that holds all the furniture (website data and files).

Comment fonctionnent les noms de domaine?

Domain names are a key part of the internet's addressing scheme, simplifying the process of navigating the web and accessing various resources. Here’s a breakdown of how domain names work.

Human-Friendly Addresses

Domain names were developed to replace numerical IP addresses (like that computers use to identify each other on the network. Because numerical IP addresses can be difficult to remember, domain names allow users to find websites with understandable and memorable terms, such as "example.com."

Système de nom de domaine (DNS)

When you enter a domain name in your navigateur web, it queries the Domain Name System. DNS is a global, distributed directory service which maps domain names to IP addresses. This system allows your browser to find the correct server on the internet where the requested website is hosted.

DNS Lookup Process

This process includes the following:

  1. Requête récursive. Your browser first sends a query to a recursive DNS server (typically provided by your internet service provider), which has the job of finding the specific IP address for the domain name you entered.
  2. Root name servers. The query starts at the root level of the DNS hierarchy if the recursive servers do not already have the answer cached. The root name servers oversee the entire DNS system and direct the query to the appropriate top-level domain (TLD) server based on the extension (.com, .org, etc.).
  3. TLD servers. Ces servers manage the specific part of the domain (like the ".com" in "example.com"). The TLD server then directs the query to the authoritative name servers for the specific domain.
  4. Authoritative name servers. Ces servers hold the actual data about the domain, including the IP address associated with the domain name. They respond with the IP address to the recursive server.
  5. Cache haute performance . To speed up future requests, the recursive server temporarily stores the DNS query results.

IP Address Resolution

Once your browser receives the IP address from the DNS server, it can make a direct request to the web server where the site is hosted. The web server then sends the website data back to your browser, allowing the web page to load.

Different Types of Domain Names

There are several different types of domain names, each serving distinct roles within the hierarchy of the Domain Name System (DNS). Here’s a breakdown of some of the most common types.

Top-Level Domains (TLDs)

Top-level domains are the highest level of domain names in the DNS structure, found at the end of a domain name (after the last dot). Examples include .com, .org, .net, which are generic TLDs (gTLDs), and .uk, .ca, .us, which are country-code TLDs (ccTLDs).

The gTLDs were originally designed for specific types of organizations (e.g., .com for commercial entities, .org for organizations), but their use has become more flexible over the years. ccTLDs are generally used by entities connected with a particular country or region and are regulated by local registries.

Domaines de second niveau (SLD)

Second-level domains are directly below a TLD in the DNS hierarchy. For example, in "example.com," "example" is the SLD. This is typically the part of the domain name that is registered by individuals or organizations when they want to establish a web presence. The SLD can be a brand name, a personal name, or any other label that the registrar allows. The combination of a second-level domain and its TLD (like "example.com") is often referred to as a "domain name".


Subdomains are a third level of hierarchy under second-level domains, and they allow further organization and partition of the space under a registered domain name. Common examples include "blog.example.com" or "shop.example.com." Subdomains can be created by the domain owner and used to separate different areas of the website or to host other services like a separate blog or an online store. They are useful for managing large websites or hosting different content and Applications Web on the same main domain name.

Domaines de premier niveau de code de pays (ccTLD)

Country code top-level domains are specific to a country or a region, denoted by two letters. For instance, ".uk" stands for the United Kingdom, ".de" for Germany, and ".jp" for Japan. These domains are typically managed by a local regulatory authority and are meant to show that a website is related to or operating in a specific country or region. They are particularly important for companies that want to tailor their websites to local markets with recognized national identifiers.

Domaines de premier niveau sponsorisés (sTLD)

Sponsored top-level domains are a subset of TLDs that are managed and used by specific communities represented by private organizations. Examples include .edu, which is reserved for educational institutions, .gov for United States government entities, and .mil for the military. These domains are sponsored by specific agencies or groups that manage the policies of these domains to ensure they serve the interests of their specific communities.

How to Choose a Domain Name?

Choosing a domain name is a crucial step for establishing an online presence, whether for a business, a personal blog, or any other type of project. Here are some key considerations to help you select an effective domain name:

  • Soyez bref et simple. Aim for a domain name that is short, simple, and easy to remember. Shorter names are easier to recall, type, and share. Avoid complex spellings and try to keep the domain name to a few memorable words or a concise phrase.
  • Use keywords wisely. Incorporate keywords that describe your business or the services you offer. This can help improve your site’s visibility and search engine ranking. For example, if you're opening a bakery, you might want to include "bakery" or "breads" in your domain name.
  • Évitez les chiffres et les tirets. Numbers and hyphens can be misunderstood when people hear your website name spoken aloud. They also complicate the spelling of your domain name. If possible, stick to alphabetic characters to avoid potential confusion.
  • Make it brandable. Choose a domain name that reflects your brand’s identity and is unique enough to stand out. A brandable name often has a unique twist to it, isn’t generic, and is appealing to your target audience. It should evoke a positive emotional response or association with your brand.
  • Consider longevity. Select a domain name that is flexible enough to accommodate your future growth and possible shifts in your business. Avoid overly specific names that could limit your business if you decide to expand or alter its focus.
  • Research the domain name. Check to ensure the domain name isn’t already taken or too similar to existing domain names, especially those of established businesses. Also, ensure that it doesn't infringe on any trademarks to avoid legal issues.
  • Choose the appropriate domain extension. While .com domains are the most popular and memorable, there are many other TLDs available, such as .net, .org, .info, or industry-specific ones like .tech, .fashion, and region-specific TLDs. Choose one that suits your business type and location.
  • Use Domain Name Generators: These tools help brainstorm ideas and find available domains by combining your initial keywords with other words and extensions.
  • Check social media availability. Ideally, your domain name should be consistent across your website and your social media profiles. Check the availability on social media sites to establish a consistent brand identity.
  • Think about localization. If your business is focused on a particular geographic area, consider including the city or state in your domain name to localize your SEO efforts and connect with local customers.

Where to Buy a Domain

You can purchase domain names from various sources known as domain registrars. These are organizations accredited by the Internet Corporation for Assigned Names and Numbers (ICANN) or national ccTLD authorities to sell domain names. Some of the most popular and reliable domain registrars include:

  • GoDaddy
  • Namecheap
  • Google Domaines
  • Bluehost
  • HostGator

These registrars often offer additional services like hosting, email accounts, and management tools, which can be beneficial if you're looking to bundle services.

Comment acheter un domaine

Here’s a step-by-step guide on how to buy a domain:

  • Recherche de nom de domaine. Start by using the search tool on the registrar's website to check the availability of your desired domain name. If it's available, you can proceed to purchase it. If not, the registrar will typically suggest related available names.
  • Choose your domain extension. Decide on your domain extension (.com, .net, .org, etc.). .com domains are the most popular, but other TLDs may be more suitable for your specific needs, especially if .com isn't available.
  • Période d'Enregistrement. Choose how long you want to register your domain for. The registration period can be from 1 year to up to 10 years. Remember, you will need to renew your domain registration before it expires to keep ownership.
  • Confidentialité et protection. Consider adding privacy protection to your domain registration. This service (often called WHOIS privacy) hides your personal information from the public WHOIS database, which is otherwise accessible to anyone on the internet.
  • Create an account and purchase. You will need to create an account with the domain registrar if you don’t already have one. Once your account is set up, you can proceed to purchase the domain. During this process, you'll provide registrant information and make a payment.
  • configuration. After purchasing, you can configure your domain settings through your registrar’s dashboard. This includes setting up Enregistrements DNS, forwarding emails, and other domain management tasks.
  • Services supplémentaires. Many registrars offer additional services like web hosting, SSL certificates, and email hosting. You can opt for these during the domain registration process or add them later as needed.

Anastazija est une rédactrice de contenu expérimentée avec des connaissances et une passion pour cloud l'informatique, les technologies de l'information et la sécurité en ligne. À phoenixNAP, elle se concentre sur la réponse à des questions brûlantes concernant la garantie de la robustesse et de la sécurité des données pour tous les acteurs du paysage numérique.