DNS is one of the most important services that is present on the internet. An internet has thousands of devices that are a part of it and each of these devices is referred to as a host. Each host could be a printer, router, computer, or any other device. Each host has a unique IP address associated with it. Apart from the IP address, each host also has a unique hostname associated with it. For example, if the hostname is LP471 and it is present in a domain technest.com, then the fully qualified domain name (FQDN) of the host is LP471.technest.com. The FQDN is used to identify the host uniquely within the DNS namespace. The DNS namespace contains some commonly used name suffixes; they are as follows:

• .com: Commercial organizations
• .edu: Educational institutions
• .gov: Government organizations
• .org: Non-profit bodies like IEEE
• .net: Networking organizations

Apart from these commonly used name suffixes, there are several others, too.