DNS
Domain Name System, the internet's directory that translates domain names to IP addresses.
Definition
The Domain Name System (DNS) is the internet's distributed directory service that translates human-readable domain names (like example.com) into IP addresses (like 93.184.216.34). DNS makes the internet usable by allowing people to remember names instead of numbers.
DNS involves a hierarchy of servers—root servers, TLD servers, and authoritative servers—that work together to resolve queries. DNS configuration includes records for websites (A/AAAA), email (MX), and verification (TXT).
Why It Matters
DNS is fundamental infrastructure that every web property depends on. DNS configuration affects website availability, email delivery, and security. DNS issues can make entire services unreachable.
Understanding DNS helps troubleshoot connectivity issues and configure domains properly.
Examples in Practice
Updating A records to point a domain to a new web server's IP address.
Using CNAME records to alias subdomains to third-party services like CDNs.
DNS propagation delays causing inconsistent access after making record changes.