What Does DNS Do and How Does It Work?

DNS (Domain Name System) is essentially the internet’s phonebook. Its primary function is to translate human-friendly domain names (like example.com) into IP addresses (such as 192.0.2.1) that computers use to identify each other on the network. Without DNS, users would need to remember long numeric IP addresses to access websites, which would make navigation much more challenging.

How Does DNS Work?

Here’s a simplified breakdown of the DNS process:

1. User Types a URL: When you type a web address (URL) into your browser, such as www.example.com, the browser checks if it already has the IP address stored in its cache. If not, it initiates a DNS query.
2. DNS Resolver (Recursive DNS Server): The DNS query is first sent to a DNS resolver (often provided by your ISP or a third-party service like Google DNS). The resolver’s job is to find the IP address for the domain name.
3. Root DNS Server: If the resolver doesn’t have the IP address cached, it contacts a root DNS server. The root server responds with a referral to the appropriate top-level domain (TLD) DNS server, such as .com for example.com.
4. TLD DNS Server: The resolver then queries the TLD server, which provides a referral to the authoritative DNS server for example.com.
5. Authoritative DNS Server: This server holds the actual DNS records for example.com, including its IP address. It responds with the IP address of the domain.
6. Returning the IP Address: The DNS resolver returns the IP address to the user’s browser, which then uses it to make a direct request to the web server hosting example.com.
7. Website Loads: The web server processes the request and sends back the website content, which is displayed in the user’s browser.

This entire process typically happens in milliseconds, allowing users to access websites almost instantly. DNS is vital for the functioning of the internet, as it simplifies access to websites and services, making it user-friendly and efficient.