What is DNS?
Domain Name System—the internet's phone book. DNS translates human-readable domain names (example.com) into IP addresses (93.184.216.34) that computers use to connect. Every website visit triggers DNS lookups, which can reveal your browsing to your ISP or DNS provider.
Also known as: Domain Name System, DNS lookup, Name resolution
DNS is one of the biggest privacy holes in normal browsing. By default, every site you visit is known to your ISP—because they handle your DNS queries.
How DNS Works
- You type "example.com"
- Your device asks a DNS resolver: "What's the IP for example.com?"
- Resolver returns the IP address
- Your device connects to that IP
The resolver (usually your ISP or Google/Cloudflare) sees every domain you look up—your complete browsing history.
DNS Privacy Problems
- Unencrypted by default: Traditional DNS is plaintext—anyone on the path can see it
- ISP visibility: Your ISP sees every site you visit via DNS
- Surveillance: Governments monitor DNS at scale
- Manipulation: DNS can be hijacked, censored, or used for redirects
Privacy-Preserving DNS
DNS over HTTPS (DoH)
- Encrypts DNS queries in HTTPS
- Hides queries from ISP (they see connection to DoH provider instead)
- Firefox, Chrome support; Cloudflare 1.1.1.1, Google 8.8.8.8
DNS over TLS (DoT)
- Similar to DoH, different protocol
- Port 853, sometimes blocked on restrictive networks
DNS Leaks
- When using VPN, if DNS goes through ISP instead of VPN = leak
- Your real IP can be exposed via DNS leak
- Always verify: dnsleaktest.com
Related Terms
DNS Leak
A security flaw where DNS queries bypass your VPN or proxy and are sent through your normal ISP connection, revealing the websites you visit even when your other traffic is protected.
DNS over HTTPS
A protocol for performing DNS resolution via the HTTPS protocol. It encrypts DNS queries, preventing ISPs, network administrators, and attackers from seeing which websites you're trying to visit.
Virtual Private Network
A technology that creates a secure, encrypted connection over a less secure network, such as the public internet. VPNs mask your IP address, encrypt your internet traffic, and can make it appear as though you're browsing from a different location.