The Domain Name System (DNS) and How It Works

The Domain Name System (DNS) is the backbone of the internet, providing a way for humans to interact with website and email addresses using easy-to-remember domain names, rather than IP addresses. In this post, we’ll take a look at how DNS works, and how it enables us to navigate the internet.

When you type a website address into your browser, the first step that occurs is a DNS lookup. This is when your computer sends a request to a DNS server, asking for the IP address associated with the domain name. The DNS server then responds with the appropriate IP address, which your browser uses to connect to the server that hosts your website.

The process of a DNS lookup is similar to looking up a phone number in a phone book. Just as a phone book contains a list of names and phone numbers, a DNS server contains a list of domain names and their associated IP addresses. When you type a domain name into your browser, it is like looking up a name in a phone book, and the IP address is like the phone number.

DNS servers are organized in a hierarchical system, with the root servers at the top of the hierarchy. The root servers contain information about the top-level domains (such as .com, .org, .biz, .info, .us and .ca), and they are responsible for directing traffic to the appropriate top-level domain server.

The top-level domain servers then direct traffic to the appropriate second-level domain servers, which contain information about specific domain names. For example, if you type into your browser, the root servers will direct traffic to the .com top-level domain server, which will then direct traffic to the second-level domain server.

DNS servers are also distributed across multiple locations to ensure that the system is resilient to failures. This is done through a process called caching, which allows DNS servers to temporarily store information about recently looked up domain names. This allows for faster lookups and reduces the load on the servers.

Domain names are required to have a minimum of 2 DNS servers associated with the domain.  This provides redundancy in the event one of the DNS servers is not responding.   The two DNS servers need to be on separate networks, again for redundancy purposes.

In summary, the Domain Name System (DNS) is a hierarchical system that translates domain names into IP addresses, allowing us to navigate the internet using easy-to-remember names.  DNS servers work together to ensure that we can reach the websites and email addresses we want, and caching helps to make the system more efficient and resilient.


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