Learn: DNS - Turning a URL into an IP Address

Welcome!You've already learned about networks, including LANs, WANs, and the Internet as a network of networks. Today, we’ll explore how DNS (Domain Name System) helps turn a URL like www.example.com into the IP address needed to access websites.

What is DNS?The Domain Name System (DNS) is like the Internet's phonebook. It translates human-friendly website addresses, called URLs, into numeric IP addresses that computers use to locate servers. Without DNS, you'd have to type IP addresses (e.g., 192.168.0.1) instead of website names!

How DNS WorksWhen you type a URL into your browser, DNS begins working to find the IP address for the server hosting the website. This process involves DNS servers, which store mappings of URLs to IP addresses. Your computer sends a request to these servers to find the correct IP address.

DNS ServersDNS servers are special computers that store records mapping URLs to IP addresses. When a DNS server receives a request, it checks its records to find the matching IP address. If the server doesn’t have the record, it communicates with other DNS servers to find the information.

Steps in DNS ResolutionWhen you enter a URL, DNS resolution follows these steps:Your browser sends a request to your ISP's DNS server.If the ISP’s server has the record, it sends back the IP address.If not, the ISP’s server queries other DNS servers until the record is found.The IP address is returned to your browser, and the website loads.This process happens in milliseconds!

Why DNS Is ImportantDNS makes the Internet user-friendly. Imagine remembering long strings of numbers like 192.168.0.1 for every website. DNS simplifies this by letting us use easy-to-remember URLs instead. It also enables websites to change their IP address without affecting visitors, since DNS updates the mapping automatically.

Review Time!Great work! You've learned about DNS and how it helps turn URLs into IP addresses. Let's review with a few final questions.