The Domain Name System (DNS) translates human-readable domain names, like google.com, into computer-readable IP addresses, like 172.217.160.142. This process allows you to access websites and online services using easy-to-remember names instead of complex numerical addresses.
Here's a breakdown of how DNS works:
1. Requesting a Website
When you type a website address into your browser, your computer initiates a DNS request. This request is sent to a local DNS server, typically provided by your internet service provider (ISP).
2. Local DNS Server Lookup
Your local DNS server checks its cache for the requested domain name. If it finds the IP address associated with the domain name, it sends it directly to your browser. This is called a cached response.
3. Root Server Query
If the local DNS server doesn't have the requested domain name in its cache, it queries the root servers. Root servers are the top-level servers in the DNS hierarchy. They provide the location of the authoritative DNS server for the requested domain.
4. TLD Server Query
The local DNS server then contacts the TLD (Top-Level Domain) server for the requested domain. For example, for google.com, it would contact the .com TLD server. This server provides the location of the authoritative DNS server for the domain.
5. Authoritative DNS Server Query
Finally, the local DNS server contacts the authoritative DNS server for the domain. This server is responsible for managing the DNS records for the domain, including the IP address associated with the domain name.
6. IP Address Returned
The authoritative DNS server returns the IP address associated with the domain name to the local DNS server, which then forwards it to your browser.
7. Website Access
Your browser uses the IP address to connect to the web server hosting the website and load the requested web page.
How DNS Makes the Internet Work
DNS plays a crucial role in the internet's functionality by:
- Simplifying website access: It allows users to access websites using easy-to-remember names instead of complex IP addresses.
- Improving security: DNS can be used to prevent users from accessing malicious websites by blocking access to known harmful domains.
- Enhancing performance: Caching DNS records reduces the number of requests to authoritative servers, improving website loading speed.
Examples of DNS in Action
- When you type facebook.com into your browser, DNS resolves the domain name to the IP address of Facebook's servers.
- When you send an email to [email protected], DNS is used to find the email server associated with the example.com domain.
- When you use a website like google.com to search for information, DNS helps you find the correct Google servers to process your query.
