Every time you open a website—whether it’s Instagram, Google, or a random blog—your device somehow figures out where that website lives on the internet. But websites use names like google.com or instagram.com, and your router only understands IP addresses, which are numbers like 142.250.190.78.
So how does this translation happen? And who actually knows what sites you’ve been visiting?
Let’s break it down simply.
Domain Names and DNS Lookup
When you type a website name into your browser, like youtube.com, your device doesn’t automatically know the IP address. It has to ask. That job is handled by something called DNS—Domain Name System.
Think of DNS like the internet’s phone book. You give it a name, and it gives you the number (the IP address).
Here’s what happens:
You type youtube.com into your browser. Your device asks your router, “What’s the IP address for this website?” Your router forwards the question to a DNS server, usually provided by your Internet Service Provider (ISP) or a third-party DNS service like Google (8.8.8.8) or Cloudflare (1.1.1.1). The DNS server looks it up (or checks its memory) and returns the correct IP address. Now your device can send the request to the real web server at that IP address.
So where is the DNS server?
It’s just another computer, located in a data center operated by your ISP or DNS provider. You don’t see it, but your router is configured to send requests to it. These servers are distributed across different cities and countries to respond quickly to nearby users.
How does it keep a copy?
DNS servers use something called caching. When someone asks for a website’s IP address, the DNS server saves it temporarily. That way, if someone else asks for the same website shortly after, the server can respond faster without checking the whole internet again. These saved results stay in the server for a short time (called TTL—time to live) before they expire and are refreshed.
What if the DNS server is hacked or tampered with?
If someone gains control of a DNS server and changes the entries, they can redirect users to the wrong IP address—possibly sending them to fake or malicious websites that look real. This is known as DNS spoofing or DNS poisoning. That’s why secure websites use HTTPS (to help you spot fakes), and DNS providers add protections like DNSSEC—a system that verifies the DNS data hasn’t been altered.
Who Can See What Sites You Visit?
Now comes the part about privacy.
When you visit a website, several parties can potentially see where you go, depending on how your connection is set up:
Your ISP (Internet Service Provider): Unless you use extra privacy tools, your ISP can see the domain names (like netflix.com, reddit.com) you visit. That’s because DNS traffic usually goes through their servers. Some ISPs also log that data—for performance, analytics, or (sometimes) selling it to advertisers.
DNS Providers: If you use a DNS service like Google DNS or Cloudflare DNS, those companies handle your domain lookups. They say they don’t log personal data, but you have to trust them on that.
Governments (in some countries): In places with strict internet control, governments can legally monitor or demand access to ISP logs. So yes, in those cases, a government might know what websites you’re visiting.
Wi-Fi Network Owners: If you’re on a public or school network, the network administrator can potentially see which domains you’re visiting, especially if you’re not using secure DNS or a VPN.
What About the Actual Content You View?
Here’s the good news: Most modern websites use HTTPS, which encrypts your data. This means that while your ISP or DNS provider might see that you visited facebook.com, they can’t see what you clicked, searched, or messaged inside that site. The content stays private between you and the website.
How to Protect Your Browsing Privacy
If you don’t want others seeing your browsing history:
Use encrypted DNS (DNS over HTTPS or DoH). Use a VPN (Virtual Private Network), which hides both your DNS lookups and IP traffic from your ISP. Use privacy-focused DNS providers like Cloudflare DNS (1.1.1.1). Keep using HTTPS websites, which most modern sites already support.
In Summary
Your router doesn’t store or know all website IPs. It relies on a DNS lookup—usually from a DNS server provided by your ISP or a third party—to translate website names into IP addresses.
These servers are located in data centers and speed up lookups by caching recent answers.
If a DNS server is hacked or altered, it could redirect you to fake websites, which is why protections like HTTPS and DNSSEC exist.
Your ISP or DNS provider can see which websites you visit, though they can’t see what you do on HTTPS sites.
In some countries, the government may access ISP logs. To stay private, tools like VPNs and encrypted DNS can help keep your activity secure.