Networking Fundamentals
What Is DNS and How Does It Work?
Every time you type a web address, the Domain Name System quietly translates that name into a number so your device knows where to connect.
The phone book of the internet
Computers route data using IP addresses, but people remember names. DNS (the Domain Name System) bridges the gap, translating a name like example.com into an IP address like 93.184.216.34. It is one of the internet's most essential and invisible services.
A lookup, step by step
When you request a name your device hasn't recently seen, a chain of queries unfolds — usually in a few thousandths of a second:
- Your device asks a resolver (often run by your ISP or a public provider) to find the name.
- The resolver asks a root server where the top-level domain (like
.com) is handled. - It then asks the .com servers where
example.comis handled. - Finally it asks
example.com's authoritative server for the exact record. - The answer travels back to your device, which connects to the returned IP address.
Caching makes it fast
Doing that full walk every time would be slow, so answers are cached at every level — in your device, your resolver, and in between. Each record carries a "time to live" (TTL) that says how long it may be cached. This is why a website change can take a while to appear everywhere: old answers linger until their TTL expires.
More than just addresses
DNS stores several record types: A and AAAA records for IPv4 and IPv6 addresses, MX records for mail servers, TXT records for verification and anti-spam, and PTR records for reverse lookups that turn an IP back into a hostname — the very lookup IP Ducky performs to show your connection's name.
Why it matters
DNS is a single point that everything depends on, which makes it both critical and a target. Understanding how a lookup flows explains a huge range of everyday issues, from "the site won't load" to why changing a domain's settings isn't instant.