DNS - The Internet's Phone Book
How your computer translates website names into addresses
What Is DNS?
DNS stands for Domain Name System. It translates human-friendly website names (like google.com) into IP addressesThe numerical addresses computers actually use to find each other, like 142.250.80.46. More Info… that computers understand (like 142.250.80.46).
Without DNS, you'd have to memorise numbers for every website. Imagine typing 142.250.80.46 instead of google.com - for every site you visit. DNS is the phone book that lets you look up names instead of numbers.
How Did Your Computer Get Its DNS Server?
Remember when your device connected to the network? The DHCPThe service on your router that automatically hands out network settings. More Info… server (your router) gave it four things - one of them was the DNS server address. Usually, your router either:
- Acts as a DNS server itself (forwarding requests to your ISP's DNS), or
- Tells your device to use your ISP's DNS servers directly
What Happens When You Type a Website Name
- You type google.com in your browser
- Your computer checks its own DNS cache - "Have I looked this up recently?"
- If not cached, it asks your DNS server: "What's the IP for google.com?"
- The DNS server responds: "It's 142.250.80.46"
- Your computer connects to that IP address to load the website
- Your computer saves the result in its cache for next time
DNS Caching - Speeding Things Up
DNS lookups are fast, but your computer is clever enough to remember recent lookups. This is called caching.
If you visit google.com and then visit it again 5 minutes later, your computer doesn't need to ask the DNS server again - it already knows the IP address. This cache typically lasts from a few minutes to a few hours, depending on the website's settings.
The DNS Hierarchy
When your DNS server doesn't know an answer, it doesn't give up. It asks other, higher-level DNS servers in a chain:
↓
.com DNS Server → google.com DNS Server → Answer: 142.250.80.46
There are only 13 root DNS server clusters in the world (with hundreds of copies spread globally). They're the starting point for finding any website.
Can You Change Your DNS Server?
Yes! You're not stuck with your ISP's DNS. Popular alternatives:
- Google DNS - 8.8.8.8 and 8.8.4.4
- Cloudflare DNS - 1.1.1.1 and 1.0.0.1 (often the fastest)
- OpenDNS - 208.67.222.222 (offers content filtering)
Changing your DNS can sometimes speed up browsing or provide additional privacy. You can change it on your router (affects all devices) or on individual devices.