DNS, or the Domain Name System, translates human-readable domain names (like google.com) into machine-readable IP addresses (like 172.217.160.142), allowing you to access websites easily. Here's a step-by-step breakdown:
1. Initiating the Query Process
It all begins when you type a website address into your web browser. Your computer needs the IP address to connect, initiating a DNS query. This is the first step in the process, initiating the translation process.
2. Querying the DNS Resolver
Your computer first contacts a DNS resolver. This is like a local directory service; it's a server pre-configured by your internet service provider (ISP) or network administrator. The resolver attempts to find the IP address locally in its cache. If the IP address is not found, the resolver begins the process of looking up the IP address from DNS servers across the internet.
3. Contacting Root Nameservers
If the IP address isn't in the resolver's cache, it queries one of the root nameservers. These are the top-level servers in the DNS hierarchy. They don't hold IP addresses for specific websites but direct the resolver to the next level – Top Level Domain (TLD) nameservers.
4. Accessing TLD Nameservers
Root nameservers will return the address of the authoritative TLD nameserver. The TLD (Top-Level Domain) represents the last part of a website address (e.g., .com, .org, .net). This TLD server holds information about all websites with that TLD, providing the next step in the process.
5. Retrieving the IP Address
The TLD nameserver directs the resolver to the authoritative nameserver for that specific domain (e.g., google.com). This nameserver has the actual IP addresses associated with the domain, completing the process and providing the actual IP address to the Resolver.
6. Returning the IP Address
The authoritative nameserver sends the IP address back to the DNS resolver.
7. Connecting to the Website
Finally, the DNS resolver sends the IP address to your computer. Your browser then uses this IP address to connect to the web server and load the website.
Example: Let's say you want to visit www.example.com. Your computer first asks its resolver. If the resolver doesn't know the IP address, it goes to a root nameserver, then to the .com TLD nameserver, then finally to the authoritative nameserver for example.com which provides the IP address. Your computer then uses this IP address to connect to the website.
