If you had to make one statement about the digital age everyone would agree on, it’s that there are too many acronyms to remember. HTTPS, URL, SEO, TLD, ICANN, DNS, the list goes on and on. Now, you can happily add FQDN — short for fully qualified domain name — to the ever-expanding list in your head.
An FQDN is a complete address for a website, computer, server or similar entity that exists on the internet. An FQDN consists of three labels, including the hostname, second-level domain name and top-level domain name (TLD), each separated by a period, ending with a trailing period. The following is an example of what an FQDN looks like:
In this example, the “www” is the hostname, “networksolutions” is the second-level domain and “com” is the TLD. Each label is separated by a period and the final period is what we refer to as the “trailing period.”
The one element that may look out of place is the trailing period. Usually when you look at a website address, you don’t see a period at the end. However, if you included a period when you entered an FQDN in your website browser, it would still resolve to the same page as the one you’d land on if you didn’t include the trailing period.
Trailing periods are required by Domain Name System (DNS) protocol because they indicate the end of the address. Thankfully, most internet browsers and relevant software include trailing periods automatically for end-users who don’t have the energy to worry about the purpose they serve or why they’re there.
A Partially Qualified Domain Name (PQDN) is very similar to an FQDN in that it is used to indicate the address of a website. The difference is that PQDNs refer to one or two labels from an FQDN, including either the hostname or the domain name. The trailing period is typically left off. So going back to our previous example, a PQDN can be the following:
If you click the example of the FQDN and the PQDN (www.networksolutions.com. and networksolutions.com, respectively), you’ll notice that both addresses go to the same landing page. This is because our website developers have configured our DNS to redirect visitors of either address to land on https://www.networksolutions.com/, which is the uniform resource locator (URL) for our website’s homepage. Creating redirects like these is common practice among website developers and automatically configured in most modern website builders.
PQDNs are not required for hosting websites, but they make it easier for website visitors to find you. Additionally, most users expect them, even if they don’t know what they are or understand how they work.
FQDNs indicate unique addresses on the internet, making them essential to the online experience. Another way to think about it is If you don’t have an FQDN, you don’t have a website people can access. They’re also required for installing SSL certificates, which is another feature expected from most websites.
Aside from websites, FQDNs are useful when you want to have a computer be discoverable on an internet network, such as when you want to access a computer remotely. This is fairly common in office environments because it makes it easier to track the activity on that computer. An FQDN for your computer makes it possible for it to be identified on the internet.
Lastly, FQDNs help you access domain services such as File Transfer Protocol (FTP) and email. For example, if you wanted to connect a domain name email to an email app on your phone manually, you would also need to know the FQDN for the mail server, which might look something like “mail.yourdomainname.com.”
The following is a quick summary of examples of FQDNs we’ve provided up to this point:
Note each label: hostname, second-level domain and TLD each separated by a period, ending with a trailing period. Also, note how the hostname for each also provides a hint to its application, such as “www” for access to a website on the World Wide Web, “mail” for access to an email server and “FTP” for access to file transfer protocol.
The hostname of an FQDN for a personal or work computer will typically be the name of your computer and the domain will be whatever has been assigned for the network.
If you need help finding the FQDN of your computer, the following links could prove useful:
And as always, if you need any other assistance when it comes to domain names and hosting, the Network Solutions team would be more than happy to help. Just let us know how we can assist you.