Understanding Internet Domains: Everything You Need to Know

In today’s digital age, where the internet rules supreme, the term “domain” has become synonymous with establishing an online presence. If you’re a business professional looking to understand the intricacies of the World Wide Web, this article is for you.

Understanding Internet Domains?

An internet domain (commonly referred to as a domain name) serves as the virtual address for an online presence. Delving deeper, let’s break it down to its core elements:

Unique Identifier and the Role of DNS

A domain name, at its core, is a unique identifier for a location on the internet. But how does this system ensure the uniqueness and efficient translation of human-friendly domain names into computer-friendly IP addresses? The answer lies in the Domain Name System (DNS).

1. The Need for Uniqueness

When we think about addresses in the real world, any ambiguity could lead to confusion. Similarly, in the vast expanse of the internet, each web server, where websites are hosted, has a unique IP address. This address is a series of numbers, such as “”, and ensures that when users want to access a website, they reach the correct server. However, remembering a sequence of numbers for each website is impractical for humans. That’s where domain names come into play. They act as a mnemonic device, translating easily remembered names like “smarthost.ie” into specific IP addresses.

2. DNS: The Internet’s Directory

Anither key element to Understanding Internet Domains is the Domain Name System (DNS). This is the internet’s equivalent of a phone directory. When you type a web address (URL) into your browser, the DNS is responsible for finding the corresponding IP address of the specific web server hosting that site. The browser then uses this IP address to retrieve and display the website.

The DNS functions hierarchically:

  • At the top are Root Servers, which know where to find information about top-level domains (TLDs like .com, .org, .ie).

  • TLD Servers have information about second-level domains within their specific TLD.

  • Authoritative Name Servers store DNS records for specific domains, providing the exact IP address for a given domain name.

3. Resolution Process

When you enter a domain name in your browser, the process goes as follows:

  • The browser first checks its cache to see if it already knows the IP address for the domain.

  • If not found, a query is made to a DNS Resolver, which is typically provided by your internet service provider.

  • The resolver asks the root server, which points it to a TLD server.

  • The TLD server then directs the resolver to the domain’s authoritative name server.

  • Finally, the authoritative server gives the site’s IP address to the resolver, and the resolver then passes it to the browser.

This entire process happens within milliseconds, ensuring swift access to websites.

4. Ensuring Uniqueness

Domain names are registered through domain registrars, such as SmartHost.ie. These entities coordinate with the centralized DNS system to ensure that every domain name remains unique. Once an entity registers a domain name, no other entity can use it until the original owner changes ownership or lets the registration expire.

In essence, the combination of domain names as unique identifiers and the DNS’s efficient resolution process ensures that internet users can quickly and accurately access the vast resources available on the web.

Hierarchical Structure

Domains have a hierarchical nature, often evident in their structure. For instance, in the domain name “blog.smarthost.ie“:

  • “.ie” is the top-level domain (TLD) representing Ireland.

  • “smarthost” is the second-level domain (SLD).

  • “blog” can be seen as a third-level domain or a subdomain.


Domains function as gateways to websites. When you type a domain into your browser, the domain name system (DNS) translates this name into its associated IP address. This system ensures users are taken to the correct web server hosting the website’s content.


Domain names are registered via a domain name registrar such as SmartHost.ie. This registration ensures that each domain name is unique and points to a specific IP address. For instance, “smarthost.ie” is unique to the Smart Host company in Ireland. Domain name registration comes with an annual fee, ensuring the domain’s owner retains rights to that specific web address.

Branding & SEO

From a business perspective, domain names are essential for branding. A memorable and relevant domain can enhance a company’s online identity. Moreover, search engines like Google use domains as one of the parameters for ranking websites. A well-chosen domain can aid in better search engine visibility.

An internet domain is much more than just an address; it’s a pivotal component of the internet’s infrastructure, facilitating user-friendly navigation and enabling businesses to establish a recognizable online identity.

Understanding Internet Domains – What are domains used for?

Domains serve two primary functions:


They provide an easy-to-remember web address. Instead of remembering IP addresses, which are a string of numbers, we remember domain names like “google.com” or “smarthost.ie“.


Domains can be essential for business branding, giving companies a unique presence on the internet.

Second-level and lower-level domains

A domain name usually consists of two or more parts. The “smarthost” in “smarthost.ie” is a second-level domain, while the “.ie” is a top-level domain (TLD). Further subdivisions, like “blog.smarthost.ie“, introduce third-level domains.

Internationalised domain names

These are domain names written in characters other than the Latin alphabet. For example, using characters from scripts like Cyrillic, Chinese, or Arabic. This ensures the web remains globally inclusive.

What is a URL?

URL stands for Uniform Resource Locators. It’s the complete web address you input in the address bar of modern browsers to access a specific page. It includes the protocol (like HTTP or HTTPS), domain name, and sometimes a specific path to a web page or other resources.

Absolute URLs vs. relative URLs

Absolute URLs are complete web addresses. They guide the browser to the specific location of resources, usually starting with “http://” or “https://”.

Examples of absolute URLs:

Relative URLs are abbreviated paths used to locate resources within the same domain. Examples of relative URLs:

  • /contact-us

  • /blog/article-title

Semantic URLs are designed to convey information about the content of the page, enhancing usability for users and search engines. For instance, “smarthost.ie/domains” is more descriptive than “smarthost.ie/page123”.

Second-Level Domain (SLD) and Top-Level Domain (TLD)

We’ve touched on this with the smarthost.ie example. “Smarthost” is the second-level domain, while “.ie” is the top-level domain. The combination provides a unique domain name.

Use in website hosting

Web hosting requires domain names to point to the hosted files on web servers. This is achieved through the Domain Name System (DNS), which translates domain names to IP addresses, guiding users’ browsers to the right server.

Country Code Top-Level Domains (ccTLD) and Internationalized Country Code Top-Level Domains (IDN ccTLD)

“.ie” is an example of a ccTLD, specific to Ireland. IDN ccTLDs cater to non-Latin scripts for specific countries.

Resale of domain names

Domains can be assets. Some businesses buy and sell domain names for profit, often facilitated by domain registrars. SmartHost can help facilitate the transfer of domain names once they have been sold.

IDN variants

These enable domains to be registered in different character sets, ensuring the internet is accessible to users globally.

Understanding Internet Domains – Conclusion

Firstly, the domain landscape is undeniably diverse. However, Understanding Internet Domains is pivotal for any organization or business professional eager to carve out a formidable online presence. Furthermore, whether you’re contemplating securing a new domain or diligently managing existing ones, mastering the intricacies of domains and URLs proves invaluable. Especially in today’s era, as the world becomes progressively interconnected, your domain transcends beyond being just an address; indeed, it epitomizes your very identity.

Glossary of terms – Understanding Internet Domains

Absolute URL

A complete web address, typically starting with “http://” or “https://”, which provides the full path to a resource on the internet.

Authoritative Name Server

A server that holds the actual DNS records (like IP addresses) for a specific domain.

ccTLD (Country Code Top-Level Domain)

A two-letter domain, like “.ie” for Ireland or “.uk” for the United Kingdom, specific to individual countries.


A human-readable address on the internet, which translates to an IP address.

Domain Name Registrar

An organization that manages the reservation of internet domain names. SmartHost.ie is a domain name registrar.

DNS (Domain Name System)

The system that translates domain names into IP addresses. This is a key element to Understanding Internet Domains and how they function.

gTLD (Generic Top-Level Domain)

Common domain extensions such as .com, .net, or .org.

IP Address (Internet Protocol Address)

A unique string of numbers that identifies each computer using the Internet Protocol to communicate over a network.

IDN (Internationalised Domain Name)

A domain name that includes characters from non-Latin scripts.

Relative URL

A shorter web address that provides the path to a resource relative to the current location.

Root Server

A server at the top of the DNS hierarchy, which knows where to locate TLD servers.

Semantic URL

A human-friendly URL that describes its content or destination.

SLD (Second-Level Domain)

The portion of a domain name located just to the left of the top-level domain. For example, in “smarthost.ie“, “smarthost” is the SLD.


A domain that is a part of the main domain. For instance, “blog.smarthost.ie” has “blog” as its subdomain.

TLD (Top-Level Domain)

The last segment of a domain name, located after the last dot. Common examples include .com, .org, and country-specific endings like .ie or .uk.

URL (Uniform Resource Locator)

The complete address used to access a webpage or other resource on the internet.

Web Server

A system that hosts websites and provides content to users via browsers.

WWW (World Wide Web)

An information space where documents and other resources are identified by URLs, interconnected through hyperlinks.


A server that translates domain names to IP addresses, typically provided by an Internet Service Provider (ISP).

IDN ccTLD (Internationalized Country Code Top-Level Domains)

A top-level domain for a specific country, but written in non-Latin characters.