A domain name (domain address) is the textual equivalent of an IP address. The most important characteristic of domain names is that they are easier to remember than IP addresses, which consist only of numbers. To create a website, a domain name is required, and each name must be unique. Therefore, we must choose a domain name that is not already taken!
A domain consists of multiple parts, called labels, which are separated by dots.
- At the end of a domain name, there is the so-called top-level domain (TLD). In the domain www.example.uk, .uk is the TLD and refers to the United Kingdom. There are several types of TLDs, and during domain registration, we must choose the appropriate ending(s) for the domain name.
- There are country code top-level domains (ccTLDs), such as .uk (UK), .rs (Serbia), .sk (Slovakia), and .at (Austria).
- There are internationalised country code top-level domains (IDN ccTLDs), created for countries that do not use the Latin alphabet, allowing them to use their own characters in domains. Examples include countries in the Arab world, China, Russia, and Greece.
- There are generic top-level domains (gTLDs), such as .com, .org, .edu, and .net. These TLDs are not tied to specific geographic locations but rather to the type of entity. For instance, .edu is for educational institutions, .org was originally for organisations, and .com was for commercial enterprises, though the latter two can now be used by anyone.
- Additionally, there is a TLD called .arpa, which is used exclusively by the Internet Engineering Task Force (the organisation that sets internet standards).
- The second-level domains (SLDs) are located before the TLD. In the domain example.uk, the entire name of the domain itself is the SLD, as .uk alone would only be the TLD. Before the SLD, there are third-, fourth-, fifth-, etc., level domains. Each label is separated by a dot, for example, example.test.com. The “test” label is the third-level domain, and the “example” label is the fourth-level domain. In the previous example, “example” is a subdomain of test.com, “test” is a subdomain of com, and so on. Generally, the SLD contains the name of the company (example.com), and the labels preceding the SLD refer to the server. Thus, mail.yahoo.com refers to an email server.
The domain name is part of the Uniform Resource Locator (URL), i.e., the web address.
- URL: https://www.rackhost.uk
TLD: .uk
SLD: rackhost
Hostname: www.rackhost.uk
A domain can point to multiple IP addresses to allow several servers to serve visitors to high-traffic websites. It is also increasingly common for a server at a given IP address to serve multiple websites with different domains. This method enables virtual web hosting, which is commonly used by web hosting service providers due to the limited number of IP addresses available.