What is a domain?
What most end users think of as a website is really a domain—more specifically, a domain is where the website is located. When you enter a URL into your browser, the domain points to the numerical IP address where the website can be found, much like the recipient’s address on a physical letter would tell a mail carrier where to deliver the letter.
What is a DNS server?
Humans think of domain names as words, such as digicert.com. But since computers communicate via numbers, not words, domain names must be translated from a human-readable language into a computer-readable language. DNS uses nameservers to translate domain names into IP addresses. TLD nameservers are just one of the four types of servers used in DNS.
A TLD refers to the letters that come after the dot in a domain’s name (.com, .org, etc.). These letters generally show a domain’s purpose, where it originated or what type of organization a site belongs to.
TLD in the DNS process
When a recursive resolver receives a query and can’t respond with information from its cache, it contacts a root server, which then refers the recursive resolver to a TLD server. The TLD server then sends the recursive resolver to the domain’s authoritative nameserver, which then provides the resolver with a final answer so the user can be directed to their intended destination.
Every website and IP address must have a unique name and be associated with a TLD. As mentioned above, .com and .org are examples of TLDs. Other major TLDs are .gov, .net, and .edu. Two-letter country codes like .uk, .ca and .de are also used for origination purposes.
But as the number of websites online has grown significantly, the selection of TLDs has also grown to include options like .info, .pizza and .travel.
A website’s TLD is a good way to gauge the purpose or origin of the site. A TLD ending in .gov or .edu signifies that the domain belongs to a government or educational institution. While .com was originally used for commercial websites, it’s now widely used by all sorts of websites. But a TLD of .biz clearly indicates that the site belongs to a business.