What is an FQDN?
A Fully Qualified Domain Name (FQDN) is a complete domain name that directs traffic to a specific device or service within a network. It provides a clear path across a network or the internet instead of relying on an IP address. FQDNs map to both web and email services and are part of the Domain Name System (DNS).
Key Components of an FQDN
Hostname
A hostname is a specific name of a machine or service that forms part of the domain. An example of this would be the mail. subdomain when it is used to identify an email server or service in the FQDN mail.unlimitedwebhosting.co.uk.
Domain Name
The domain name component is the registered domain for example unlimitedwebhosting in www.unlimitedwebhosting.co.uk. People usually choose domain names to be specific and unique for their site or service. Once someone registers a domain, no one else can register it under the same TLD. Secure yours today before it’s taken.
Top-Level Domain (TLD)
This forms the end of a FQDN and is used to potentially identify the type of organisation or its geographical region. For example in the domain unlimitedwebhosting.co.uk the .co.uk signifies this organisation is company (.co) operating in the United Kingdom (.uk).
However, the use of TLDs has evolved since their inception with many creative ways to use different TLDs. Including ccTLDS (Country-code top level domains), a great example of this creativity is Bitly which uses the Libyan ccTLD .ly for its domain bit.ly.
When formed these elements form the FQDN, which provides an exact address within the DNS hierarchy.
Why FQDNs Are Important
Clear Identification
FQDNs provide the exact location within a network. This is crucial for internet services like web hosting and email hosting when misrouting can cause critical issues.
DNS Resolution
Via FQDNs DNS servers are able to map readable domain names onto IP addresses including both IPv4 and IPv6 enabling users to easily access and navigate different services across a network or internet.
Security and Configuration
Different security systems and tools rely on FQDN for configuration including SSL/TLS certificates which require that the domain and certificate name are an exact match to enable secure connections.