What is a FQDN? The Beginner’s Guide to Fully Qualified Domain Names
A fully qualified domain name (FQDN) is a precise and unambiguous domain that directs users to the exact location of online/ internet resources, such as websites or servers.
In simpler terms, a FQDN is the full web address that leads you directly to a specific website or webpage. Think of it like the “X” on a treasure map leading exactly where you want to go online.
This article will explain what an FQDN is, its role in URLs, its relationship with Domain Name System (DNS) and web servers, why it’s important, and how to optimize your own FQDN.
The Domain Name System
To grasp the concept of fully qualified domain names, it’s helpful to understand what they do and why they matter.
How an FQDN works
Each time you search for something online, your device sends and receives data packets between various systems in the background. This process happens in a fraction of a second, so fast you barely notice it.
To achieve this incredible feat, every web server or device is given a corresponding IP address—a set of numbers that allows your computer or operating system to seamlessly interact with others.
Now, you must be wondering, “What do IP addresses have to do with a fully qualified domain?”
While computers may seem like they process words, they actually rely on numerical data. When you enter a domain, your web server checks to see if the information or corresponding IP address has already been stored in your cache. If not, it directs your query elsewhere.
This is where the Domain Name System (DNS) comes in. The DNS records Fully Qualified Domain Names and their corresponding IP addresses. This domain management system allows computers to quickly identify an IP address based on its more user-friendly, human-readable domain names instead.
Instead of typing a complex string like 172.64.145.59, you can enter the FDQN into a web browser, and the DNS will handle the lookup for you.
Are the Uniform Resource Locator (URL) and FQDN the same?
A URL might seem like a fully qualified domain name because it has every component of a complete domain name. However, the Hypertext Transfer Protocol or “HTTP” facilitates data transfer over the internet, making its role different from that of an absolute domain name.
It’s important to understand that while all URLs contain a complete domain name, FQDNs are not the same as URLs. In the DNS records, an FQDN can be used in place of a URL, with the protocol (HTTP or HTTPS) usually assumed by default.
4 elements of an FQDN
So, what makes a fully qualified domain name?
A complete domain name comprises three main components: the top-level domain (TLD), the second-level domain, and the subdomain. Sometimes, a fully qualified domain name may also include a hostname.
To explore the structure of an FQDN further, let’s examine this URL:
http://www.shop.fullyqualifieddomains.com
As we’ve covered earlier, this URL contains a fully qualified domain name. Now, let’s identify which elements of this is its complete address.
Before we begin, note that while in the DNS hierarchy, the top-level domain comes first, followed by the second-level domain and the subdomain; these are presented in reverse order, separated by dots (.).
In DNS records, an FQDN is read from right to left, reflecting this hierarchal structure.
Top-level domain
From our sample URL above, .com is our top-level domain (TLD). While this holds the highest level in the DNS hierarchy, it does not tell us much about the complete address itself.
A TLD is the most general categorization of a domain. Additionally, there are numerous types of TLDs to choose from. The .com domain name, much like .org, .net, and .biz, belongs to some of the common generic TLDs (gTLDs), including country-code TLDs (ccTLDs), .ca, and .us.
To be more specific with your TLD, you can go for a sponsored, purpose, or brand top-level domain instead.
Second-level domain
The second-level domain (SLD) is located directly to the left of the TLD. In our example URL, this would be ‘fullyqualifieddomains.’
This is the only portion of a complete domain name that’s entirely customizable. With its naming flexibility, SLDs are the components of an FQDN most closely associated with an organization’s name or brand.
That said, while SLDs are unique identifiers, they alone do not constitute a fully qualified domain name. However, we’ll explore this further later.
Subdomain
A subdomain organizes and categorizes sections or services within a domain, providing distinct namespaces or a hierarchical structure under the primary domain.
Our sample URL represents this by ‘shop’, which suggests that the platform or page may be selling FQDNs or other related resources.
Besides services, many subdomains can also reflect distinct departments, sections, and other categories relevant to the domain’s niche.
Hostname
The hostname appears in the leftmost part of the domain just after the HTTP/s protocol, identifying a computer or device connected to a network.
It’s commonly used to represent services like the web server(‘www’), mail servers (‘mail’), or File Transfer Protocol (‘ftp’) servers.
Essentially, hostnames serve as the human-readable identifier that maps to an IP address, granting access to devices on a local network.
Partially qualified domain name vs fully qualified domains
As the name suggests, a partially qualified domain name (PQDN) represents a portion of your fully qualified domain name. A PQDN may include only the hostname or part of the domain structure, excluding the top-level domain (TLD).
It’s important to note that using only the hostname as your PQDN is less reliable than using the entire domain itself. While a hostname can uniquely identify the IP address of a specific computer or device on a shared network, its accessibility may be limited.
Thus, ensuring that your domain-based PQDN can still uniquely identify your platform is a good practice.
Locating an IP address via FQDN on a web server may not always be optimal, especially if an FQDN is too long. In this situation, users enter general or vague queries in their web browsers as PQDNs offer a more convenient solution.
Why PQDNs matter
PQDNs aren’t required for web server hosting. Still, they make it easier for users to locate you on the DNS server and access resources within your domain. As a result, many website developers configure as many PQDNs as possible to redirect visitors to the correct IP addresses.
Other functions of a fully qualified domain name
Beyond pinpointing the exact location of a resource in the DNS server, an FQDN is essential for accessing domain services and boosting your search engine optimization (SEO) efforts.
Here are a few essential uses of an FQDN:
Identifying network resources
An FQDN uniquely and accurately identifies network resources, servers, routers, and other devices on the internet. By eliminating ambiguity, an FQDN ensures seamless network management.
Hosting on multiple web servers
Websites are typically associated with their FQDN. This is why web servers use your FQDN instead of your IP address when hosting. As such, you can easily host multiple websites on a single server, each with its own FQDN.
DNS organization and resolutions
One of the significant benefits of ab FQDN is its ability to structure resources within the DNS hierarchy. Its ability to logically group assets simplifies DNS management and makes locating specific resources much more straightforward.
Additionally, network administrators can efficiently identify and troubleshoot issues since the DNS resolves queries step by step.
What can your FQDN do for you?
Since an FQDN is easier to remember than an IP address, it’s the preferred identifier for internet interactions, such as securing network infrastructure, communication, and web services.
Some key uses include:
Acquiring a SSL/TSL certificate
A TSL/SSL Certificate allows web browsers to establish encrypted communication with websites. The server’s identity is verified using its FQDN to ensure secure network connections.
Securing remote host connections
When connecting to remote hosts or virtual machines, an FQDN helps the DNS accurately locate the server. Relying on the hostname alone may lead to resolution failures if the local DNS cannot expand it into a full name.
While using an IP address is also possible, an FQDN simplifies the process by letting the DNS server find your corresponding IP address. Once a match is found, it connects the remote host directly, often prompting a login screen.
In some cases, an FQDN may also be the only option, especially when connecting to a remote host outside your Internet Service Provider (ISP).
Gaining entry to domain-specific services
An FQDN is designed to specify the full path or directory or a website or webpage. This makes them essential for accessing FTP servers, configuring email services, securely identifying and authenticating hosts, and specifying intended host servers in Telnet connections.
How to find your FQDN
To fully manage and expand your website, you must know how to access your own FQDN. In fact, without an FQDN, your website won’t be accessible to others.
So, where do you find your FQDN?
Different operating systems (OS) have their own process for locating a fully qualified domain name, but it’s as easy as 1-2-3! Find your OS below to discover what your FQDN is!
Windows
For Windows users, check your system settings for your FQDN. To access it, navigate to your Control Panel or Click the Windows button and Search for Settings/System Settings.
- In Settings, locate and click on the System tab.
- From there, scroll down and select About
Your fully qualified domain will be listed under Device Specifications as Device Name. To change it, you can click on the Rename this PC button, which can be found in the upper-right corner of your screen.
Locating your FQDN through terminal or command prompt
Another way to access your FQDN on a Windows operating system would be to go through Terminal or Command Prompt, both of which can also be found in the list of apps when you click the Start or Windows button.
Once you select either, a black screen will appear. Type in ‘hostname’ and your FQDN appears automatically.
MacOS
For Mac users, open your System Settings / Preferences to find your FQDN. Click on Sharing, in there you’ll find your FQDN listed as your Computer Name. You can also use Terminal or Command Prompt to find your FQDN.
Linux
Unlike a Mac or Windows Operating System, Linux OS only provides its FQDN through the Terminal. To enter, press Ctrl+Alt+T. Once the application appears, enter the command line: hostname-fqdn.
Conclusion
We’ve explored how FQDNs are vital for various online activities, including securing websites with SSL certificates, connecting to remote servers, and routing email. We’ve also highlighted their importance to web and DNS servers. Now that you know how to locate an FQDN across different operating systems, you should have the knowledge to further explore and effectively use FQDNs.
If you’re ready to take the next step and register your own domain, Domain.com offers a reliable solution. With a broad selection of domain extensions, competitive pricing, and top-tier customer support, Domain.com ensures a smooth and secure experience for managing your online presence.
