Top-level Domains come at the end of domain names, and are important for classifying domain names, as well as essential for DNS lookups.
In the DNS hierarchy, a top-level domain (TLD) represents the first stop after the root zone. In simpler terms, a TLD is everything that follows the final dot of a domain name. For example, in the domain name ‘google.com’, ‘.com’ is the TLD. Some other popular TLDs include ‘.org’, ‘.uk’, and ‘.edu’.
TLDs play an important role in the DNS lookup process. For all uncached requests, when a user enters a domain name like ‘google.com’ into their browser window, the DNS resolvers start the search by communicating with the TLD server. In this case, the TLD is ‘.com’, so the resolver will contact the TLD DNS server, which will then provide the resolver with the IP address of Google’s origin server.
The Internet Corporation for Assigned Names and Numbers (ICANN) has authority over all TLDs used on the Internet, and it delegates the responsibility of these TLDs to various organizations. For example, a U.S. company called VeriSign operates all ‘.com’ and ‘.net’ TLDs.
Another purpose of TLDs is to help classify and communicate the purpose of domain names. Every TLD will tell you something about the domain that precedes it; let’s look at some examples:
TLDs themselves are also classified into one of several groups.
There are now so many TLD options available that the choice can be overwhelming for someone trying to register a new domain name. For years ‘.com’ was seen as the only option for businesses that want to be taken seriously. But experts predict that as the supply of ‘.com’ domains dwindles and some of the newer TLDs continue to pick up steam, we will see a major shift in the perception of alternative TLDs. With big companies like Twitter and Apple starting to adopt alternative TLDs for their products (t.co and itun.es, respectively) we are already seeing that shift in action, so it may be better to create a clever and memorable domain name using an alternative TLD, than to insist on a ‘.com’ domain.