DNS stands for Domain name system. DNS is the phonebook of the internet. Humans access information online through domain names, like google.com or Silvertoad.co.uk as this is a much easier way to remember an address like 192.168.1.1. Web browsers interact through internet protocol addresses. DNS translates domain names to IP addresses so browsers can load the internet resource.
The process of DNS resolution involves converting a hostname into a browser-friendly IP address. An IP address is given to each device on the internet. When a user wants to load a webpage, a translation must occur between what a user types into their web browser and the machine friendly address to locate the webpage.
In order to understand the process behind the DNS resolution, it’s important to learn about the different hardware components a DNS query must pass between. For the web browser, the DNS lookup occurs in the background and requires no user input.
There are 4 DNS servers involved in loading a webpage. DNS recursor is a server designed to receive queries from client machines through applications such as web browsers. Typically the recursor is then responsible for making additional requests in order to satisfy the client’s DNS query.
The root name server is the first step in resolving a host name into an IP address. It can be thought of like an index in a library that points to different racks of books – typically it server as a reference to other more specific locations.
TLD name server is the top level domain server. This name server is the next step of search for the specific IP address, and it hosts the last portion of a hostname for example Silvertoad.co.uk it would resolve the .co.uk portion.
The authoritative name server is the final name server and the last stop in the name server query. If the authoritative name server has access to the requested record, it will return the IP address for the requested hostname back to the DNS recursor that made the initial request.