A Fully-Qualified Domain Name (FQDN) is a complete web address that shows the precise location of a webpage in the hierarchy of a DNS (Domain Name System). It consists of several parts including a host name, sub-domain, domain name, and a top-level domain. For instance, ‘www.example.com’ where ‘www’ is the host, ‘example’ is the domain name and ‘com’ is the top level domain. Each part is separated by a period. It’s vital to know that an FQDN always starts with the host, moving all the way to the top of the DNS hierarchy.
Fully-Qualified Domain Name Examples
1. Example
The first example of a Fully-Qualified Domain Name (FQDN) is ‘www.google.com’. This is the complete web address you would type into a browser to access Google’s homepage.
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In this FQDN, ‘www’ is considered the hostname. It typically represents a specific service or server on a network, in this case, the world wide web service of Google.
The ‘google’ part is the domain name. It is unique to the organization and is typically a name that assists users in identifying the entity behind the website. In this scenario, ‘google’ refers to Google Inc., the multinational technology company.
Last but not the least, ‘com’ is the top-level domain (TLD). TLDs classify domains based on their purpose or the geographical area they represent. The ‘.com’ TLD is commonly used for commercial purposes, which fits with Google’s operations as a for-profit corporation.
2. Example
The second example of a Fully-Qualified Domain Name (FQDN) is ‘mail.yahoo.com’. This specific address takes you directly to Yahoo’s email service.
‘Mail’ in ‘mail.yahoo.com’, is the host name. It indicates the specific service or server on the Yahoo network that the web address points to. In this case, it’s Yahoo’s mail service.
‘Yahoo’ is the domain name. It’s unique to the organization behind the service. Here, the domain name signifies Yahoo Inc., the well-known web services provider.
‘Com’ is once again the top-level domain (TLD). As with the previous example, the ‘com’ TLD is usually designated for entities engaged in commercial activities, aligning appropriately with Yahoo’s status as a corporation.
3. Example
The third example of a Fully-Qualified Domain Name (FQDN) is ‘blog.example.org’. This FQDN would direct you to a blog located within the ‘example’ domain.
‘Blog’ in ‘blog.example.org’ is the host name. This suggests that the web address would take the user to a particular service under the ‘example’ domain, in this instance, a blog.
‘Example’ serves as the domain name. This is a unique identifier that represents the organization or entity responsible for the associated web content. In this hypothetical instance, the ‘example’ domain could therefore belong to any organization or entity.
‘Org’ is the top-level domain (TLD) in this example. It’s conventionally used by non-profit organizations, indicating that the ‘example’ domain may possibly belong to or be associated with such an organization.
Conclusion
A Fully-Qualified Domain Name (FQDN) pinpoints a webpage’s exact location within the DNS hierarchy, and is constructed of several interconnected components. Through accurate interpretation and application of these parts, including the host, sub-domain, domain name, and top-level domain, anyone can navigate the web quickly and efficiently.
Key Takeaways
- A Fully-Qualified Domain Name (FQDN) is the complete address of a website, indicating its specific location in the Domain Name System.
- An FQDN consists of four parts: the host name, sub-domain name, domain name, and top-level domain.
- The host name points to the specific server or service on a network.
- The domain name is unique to the organization and identifies who owns the website.
- The top-level domain is the suffix in the FQDN that can suggest the purpose or geographic area of the website.
Related Questions
1. What does www stand for in a web address?
In a web address or URL, ‘www’ stands for the World Wide Web. It is the host name and is often used to denote that the address leads to a website.
2. Are all FQDNs accessible over the Internet?
Not all FQDNs are publicly accessible over the Internet. Some may be intranet addresses or part of a private network.
3. How is an FQDN different from a URL?
A URL is a broader term that includes the protocol (e.g., http, https, ftp) and often the path to a specific webpage or file, whereas an FQDN primarily refers to the domain name structure that specifies a server’s exact position within the DNS hierarchy.
4. Is the use of ‘www’ as a host necessary for all FQDNs?
No, ‘www’ is a convention, not a requirement. A web server can be configured to handle requests for ‘example.com’ and ‘www.example.com’ differently or the same.
5. Can an FQDN have more than one subdomain?
Yes, an FQDN can include multiple subdomains. For example, ‘www.blog.example.com’ where ‘www’ and ‘blog’ are subdomains of the primary domain ‘example.com’.
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