Understanding DNS: The Internet’s Address Book Explained
DNS, or Domain Name System, is like the internet’s phonebook. When you type a website address into your browser, your computer doesn’t directly know where that server is located. Instead, it asks a DNS server to translate the human-readable domain name (like google.com) into a numerical IP address (like 142.250.185.46) that computers use to communicate.
How DNS Works
When you type a URL, your computer performs a DNS lookup in milliseconds. It queries a resolver (usually your internet service provider’s server), which checks its cache. If the address isn’t cached, the resolver queries root nameservers, then top-level domain servers, and finally the authoritative nameserver for that specific domain. This information is returned to your computer, which then connects to the web server.
Caching and Speed
DNS results are cached at multiple levels to improve speed. Your computer, router, and ISP all cache DNS records, meaning repeated visits to the same website happen instantly without querying distant servers. This caching mechanism is why your internet feels faster when revisiting favorite sites.
DNS and Security
DNS can be vulnerable to attacks where malicious actors redirect your requests to fake servers. Using secure DNS services like Cloudflare’s 1.1.1.1 or Google Public DNS can protect against these threats and improve privacy by preventing your ISP from logging your browsing history.