Domain names provide a human-readable and memorable way to access resources on the Internet. They play a crucial role in navigating the web and accessing websites, email servers, FTP servers, and other network resources. The hierarchical structure of domain names, along with the DNS infrastructure, ensures efficient and reliable resolution of domain names to their respective IP addresses.
In the logical view of a network, domain names play a significant role in identifying and accessing resources on the Internet. A domain name is a user-friendly, alphanumeric name that represents an IP address or a group of IP addresses associated with a particular entity, such as a website, server, or network.
Hierarchy and Structure: Domain names follow a hierarchical structure that reflects the organization and administration of the Internet. A domain name is composed of multiple labels or segments separated by dots (periods). The labels are read from right to left, with the top-level domain (TLD) being the rightmost label.
Example: www.example.com
“com” is the top-level domain (TLD).
“example” is the second-level domain (SLD).
“www” is the host or subdomain.
Top-Level Domains (TLDs): TLDs represent the highest level in the domain name hierarchy. They can be generic TLDs (gTLDs) like .com, .net, .org, or country code TLDs (ccTLDs) like .us, .uk, .ca, which correspond to specific countries. Newer TLDs, known as generic top-level domains (gTLDs), have been introduced, such as .guru, .shop, .app, allowing for more specialized domain name choices.
Domain Name System (DNS): The Domain Name System is a decentralized hierarchical naming system that translates domain names into their corresponding IP addresses. It acts as a directory for the Internet, allowing users to access resources by their domain names instead of remembering complex IP addresses. DNS servers maintain databases containing mappings of domain names to IP addresses.
Fully Qualified Domain Name (FQDN): An FQDN represents a complete domain name, including all labels and the TLD. It provides an absolute reference to a specific resource on the Internet. For example, www.example.com is an FQDN.
Subdomains: Subdomains are a way to further organize and categorize resources within a domain. They are created by adding a prefix to the domain name. For example, blog.example.com is a subdomain of example.com.
Domain Name Registration: Domain names are registered through accredited domain registrars. Individuals, organizations, or businesses can purchase and register domain names for a specific duration, typically ranging from one to ten years.
Domain Name Resolution: When a user enters a domain name in a web browser or requests a resource by its domain name, the DNS system resolves the domain name to its corresponding IP address. This process involves querying DNS servers to find the IP address associated with the domain name, enabling the user to establish a connection with the desired resource.