On this page you’ll learn about Domain Name System (DNS) with answers to the following questions:
What is DNS?
What is DNS Resolution?
What is a top level domain (TLD)?
What is a second level domain (SLD)?
What is a third level domain?
What are the types of DNS service?
How Does DNS Route Traffic To Your Website?
What is DNS?
Every smart phone, laptop or the servers on the web has a unique Internet Protocol (IP) address which identifies such devices allowing them to relay information online. You can call these IP addresses the telephone numbers of devices online. These IP addresses are represented as a series of numbers and/or letters, for example, 84.24.12.422 (IPv4) or 3001:353:A65:0:0:1:24 (IPv6).
So if you know the IP address of a device or website you can use it to find or connect with it online. But because IP addresses are hard to use and remember, DNS is needed to act as a bridge between people and IP addresses allowing you to connect to a device or website using memorable domain names. It’s because of DNS, when you open a web browser and go to a website, you don’t have to remember and enter a long alpha-numerical IP address. You can instead enter a domain name like rocket.domains to visit a website.
A DNS service, such as RocketDNS, is a globally distributed service that converts human readable names like rocket.domains into IP addresses. The Internet’s DNS system works much like a telephone directory by managing the mapping between names and numbers. DNS servers translate requests for domain names into IP addresses, controlling which server a user will find when they type a domain name into their web browser. These requests are called DNS queries.
What is DNS Resolution?
We have learned that DNS makes websites, email systems, and web applications available on the Internet by mapping easy to remember domain names to not-so-memorable IP addresses. The process of translating a domain name, such as rocket.domains, into its corresponding IP address is called a DNS resolution. DNS resolution is made possible by specialized servers which translate domain names into IP addresses which in turn allows users to reach their desired website or application online. DNS resolution, therefore, makes it possible visitors to type memorable domain name names into a browser to reach websites instead of having to use complex alphanumerical IP addresses.
What is a top level domain (TLD)?
Top level domains (TLDs) are the highest level of organization of domains on the Internet. There are mainly two kinds of TLDs: Generic TLDs such as .com, .net, .domains etc., and Geographic TLDs for countries and regions such as .uk, .london, .nyc. These TLDs act as suffixes to your domain names.
What is a second level domain (SLD)?
When you register a domain name, you don’t actually own the TLD, you own a Second Level Domain on that TLD. In other words, two or more websites can have the same TLDs such as .com but they will always have a unique Second Level Domain such as DNSNAUT.COM, GOOGLE.COM, SPACESUITE.COM, or ROCKET.DOMAINS.
In the above domain examples, DNSNAUT, GOOGLE, SPACESUITE and ROCKET are Second Level Domains (SLDs)
What is a third level domain?
Third Level Domains are known as Subdomains which are built on Second Level Domains. For example, the most common subdomains are www, blog. A subdomain can, therefore, look like www.google.com and my.rocket.domains where www and my are the subdomains, google and rocket are the second level domains, and .com and .domains are the top level domains.
What are the Types of DNS Servers?
There are two types of DNS servers: authoritative and recursive.
Authoritative DNS: An authoritative DNS service provides an update mechanism that developers use to manage their public DNS names. It then answers DNS queries, translating domain names into IP address so computers can communicate with each other. Authoritative DNS has the final authority over a domain and is responsible for providing answers to recursive DNS servers with the IP address information. An example of authoritative DNS system is Rocket Domains’ RocketDNS.
Recursive DNS: Clients typically do not make queries directly to authoritative DNS services. Instead, they generally connect to another type of DNS service known a resolver, or a recursive DNS service. A recursive DNS service acts as an intermediary who can get the DNS information on your behalf. If a recursive DNS has the DNS reference cached, or stored for a period of time, then it answers the DNS query by providing the source or IP information. If not, it passes the query to one or more authoritative DNS servers to find the information.
How Does DNS Route Traffic To Your Website?
The DNS uses the following steps to map domain names to IP addresses, making it possible for users to search for website and send emails using memorable domain names instead of alpha numerical IP addresses.
- You open a web browser, enter a domain or web address such as rocket.domains in the address bar, and hit Enter. Your browser sends a message to the network asking for help (this is called a DNS query)
- Your computer queries (contacts) one of the machines that your ISP (Internet Service Provider) assigned to your computer, called Recursive Resolvers, which will first try and find the IP address in its cache.
- If your ISP’s Recursive Resolver does not have the IP address in its cache, they query the DNS Root Name Server for the IP Address.
- The Root Name Servers refer your ISP’s Recursive Resolver to relevant TLD Name Servers by examining the Top Level Domain you entered in your browser.
- Each TLD has its own set of Name Servers, and after the Resolver asks them for the IP address, they refer it to another set of Authoritative DNS Servers by Reviewing the Second Level Domain of the query. For example, in your query the TLD is .domains and the Second Level Domain is ‘rocket’.
- Your ISP’s Recursive Resolver then queries the referred Authoritative DNS Name Servers for the IP address. Each domain has an assigned set of authoritative DNS Name Servers that record everything about the domain including the IP address(es).
- Finally, your ISP’s Recursive Server returns the ‘A Record’ to your computer which transmits the IP address to your browser. The browser then opens a connection to rocket.domains and loads the website. the entire process happens in a blink of an eye.