A top-level domain (TLD), in the DNS hierarchy is the first stop after a root zone. A TLD, in simpler terms, is anything that follows the last dot of a domain name. TLDs are, for example, the domain name “google.com” where “.com” is the TLD. Other popular TLDs are ‘.org, ‘.uk, and ‘.edu.
The DNS lookup process is aided by TLDs. The DNS resolvers initiate the search by communicating to the TLD servers for all uncached queries. The TLD in this example is “.com”. Therefore, the resolver will contact TLD DNS server to get the IP address for Google’s origin web server.
The Internet Corporation for Assigned Names and Numbers, (ICANN), has the authority to control all TLDs on the Internet and delegate responsibility for these TLDs. VeriSign, an American company, manages all TLDs in the ‘.com/.net’ domains.
TLDs also serve to classify and communicate domain names’ purpose. Each TLD will reveal information about the domain before it. Let’s take a look at some examples.
- ‘.com’ is for commercial businesses.
- ‘.gov’ is used for U.S. government agencies.
- ‘.uk’ refers to domains located in the United Kingdom.
TLDs are themselves also classified into one or more groups.
What are the various types of TLDs available?
- Generic DNS: gTLDs (gTLDs), include some of the most common domain names on the internet, such as “.com”, “.net” and “.org”. Although the Internet Corporation for Assigned Names and Numbers used to severely restrict the creation of new gTLDs in the past, these restrictions were lifted in 2010. There are now hundreds of lesser-known generic top-level domains like ‘.top’ and ‘.xyz.
- Country code TLDs: TLDs (ccTLDs), are reserved for countries, sovereign states, or territories. Some examples include ‘.uk’, “.au” (Australia), and “.jp” (Japan). The Internet Assigned Numbers Authority, which is managed by ICANN is responsible for selecting the appropriate organizations to manage ccTLDs in each location.
- Sponsored tLDs: These TLDs usually represent geographical, ethnic, and professional communities. Each sponsor, TLD (sTLD), has a designated sponsor who represents the community. Google sponsors the TLD ‘.app’, which is intended for developers. The General Services Administration sponsors ‘.gov’, which is a TLD intended for the U.S government.
- Infrastructural DNS: This TLD category only has one TLD: “.arpa”. Named after DARPA, the U.S. military organization that pioneered the Internet, “.arpa” was the first TLD to be created. It is now used for infrastructural tasks such as facilitating redirected DNS lookups.
- Reserved TLDs: There are some TLDs that are on a reserve list. This means they are not available for permanent use. For example, “.localhost” is reserved for local computer environments and “.example” is reserved for example demonstrations.
Are TLDs Important?
The number of TLD options available can make it difficult to choose the right one for you. The only choice for serious businesses was ‘.com’ for many years. Experts predict that there will be a shift in perception towards alternative TLDs as the number of domains available to ‘.com’ decreases and some of the more recent TLDs gain momentum. We are already witnessing big companies such as Apple and Twitter adopting alternative TLDs (t.co/itun.es), so it might be a better idea to use an alternative TLD to create a memorable domain name than to insist on a “.com” domain.