The Domain Name System (DNS) acts as the Internet’s directory service, akin to a phonebook. When we access websites like nytimes.com or espn.com, we’re using domain names. However, behind the scenes, web browsers communicate through Internet Protocol (IP) addresses. DNS steps in to translate these domain names into IP addresses, facilitating the loading of online resources.

Every device connected to the Internet possesses a unique IP address, serving as its identifier for other devices to locate it. DNS servers play a crucial role in eliminating the need for humans to memorize these IP addresses, whether they’re the simpler IPv4 format like 192.168.1.1 or the more intricate alphanumeric IPv6 addresses like 2400:cb00:2048:1::c629:d7a2.

DNS resolution is essentially the translation of a user-friendly website name, like www.example.com, into a computer-friendly IP address, such as 192.168.1.1. Just like how every home has a unique street address, every device on the Internet has its own IP address, essential for locating it in the vast digital landscape.

When you want to load a webpage, there’s a bit of behind-the-scenes magic happening. Your web browser translates what you type (like example.com) into the machine-friendly address needed to locate that webpage.

Understanding DNS resolution involves knowing about the different hardware pieces involved in the process. For the average user, this happens seamlessly, with the web browser handling the DNS lookup without any need for direct interaction.

4 DNS servers involved in loading a webpage:

When loading a webpage, several DNS servers are typically involved in the process. Here are four of them:

1. Recursive DNS Server (Resolver): This is usually the first DNS server queried by your device when it needs to resolve a domain name. It’s responsible for finding the IP address associated with the domain name. If it doesn’t have the information cached, it will recursively query other DNS servers until it finds the authoritative DNS server for the domain.
2. Root Name Server: The root name servers are the starting point for DNS resolution. They maintain a list of authoritative DNS servers for all top-level domains (TLDs) like .com, .org, .net, etc. When the recursive DNS server doesn’t have the IP address cached, it queries one of the root name servers to find out which authoritative name server to contact next.
3. Top-Level Domain (TLD) Name Server: These servers handle the second level of DNS hierarchy and are responsible for maintaining information about domain names within a specific top-level domain. For example, if you’re trying to resolve a domain under .com, the TLD name server for .com would be queried next after the root name server.
4. Authoritative DNS Server: This is the final stop in the DNS resolution process. It holds the actual IP address information for the domain name in question. Once the recursive DNS server receives this information from the authoritative DNS server, it caches it for future use and returns the IP address to your device, allowing your browser to load the webpage.

These four types of DNS servers work together to ensure that users can access websites by translating domain names into IP addresses.