DNS (Domain Name System) is a decentralized naming system for computers and services connected to the Internet. It serves as the infrastructure that translates human-friendly hostnames like example.com into machine-readable IP addresses such as 93.184.216.34, enabling network routing without requiring users to memorize numeric identifiers.
How it works
The resolution process starts when a client sends a query to a recursive resolver. The resolver queries root nameservers, Top-Level Domain (TLD) nameservers, and finally authoritative nameservers to find the specific IP address. To minimize latency, DNS data is heavily cached at multiple levels, including the local OS and ISP infrastructure.
DNS is critical for almost all network activities, including web browsing, email routing, and API communication. Administrators manage DNS via zone files containing specific resource records: A records for IPv4 mapping, AAAA for IPv6, and MX for specifying mail servers responsible for accepting email messages.
Technical fact: DNS primarily uses UDP port 53 for small queries due to its low overhead, but falls back to TCP port 53 when response data exceeds 512 bytes or during zone transfers (AXFR).