DNS (Domain Name System)
The system that translates domain names into IP addresses.
DNS is often called the "phonebook of the internet." When you type a domain name into your browser, DNS servers translate that name into the IP address where the website is hosted.
How DNS works:
- You enter a domain name in your browser
- Your computer asks a DNS resolver for the IP
- The resolver queries root servers, TLD servers, then authoritative servers
- DNS responds with the IP address
- Your browser connects to that IP and loads the website
This happens in milliseconds, every time you visit any website.
DNS Components:
- Root Servers: Top of the DNS hierarchy (13 sets globally)
- TLD Servers: Handle queries for each TLD (.com, .org, etc.)
- Authoritative Servers: Hold the actual DNS records for domains
- Resolvers: Your ISP's servers that cache and resolve queries
Why DNS is Distributed: No single server could handle all DNS queries globally. The distributed system provides:
- Speed through caching
- Resilience through redundancy
- Scalability across billions of domains
Why It Matters
Understanding DNS helps you troubleshoot website issues, set up email correctly, and manage your online infrastructure. When your website is down, DNS misconfiguration is often the culprit.
Practical Example
When someone types yourbusiness.com, DNS translates that to something like 192.168.1.1, telling their browser which server to connect to. If you move to a new web host, you update DNS records to point to the new server's IP.
Related Terms
A Record
TechnicalA DNS record that maps a domain name to an IPv4 address.
DNS Propagation
TechnicalThe time it takes for DNS changes to spread across all servers worldwide.
MX Record
EmailA DNS record that specifies mail servers responsible for receiving email for a domain.
Nameserver
TechnicalA server that stores DNS records and responds to queries about domain names.
Explore More Terms
Browse our complete glossary of domain name terminology.