DNS (Domain Name System)

Overview

The Domain Name System (DNS) is a hierarchical and decentralized naming system for computers, services, and other resources connected to the Internet. It translates human-readable domain names into IP addresses, essentially functioning as the Internet’s phone book.

Detailed Explanation

DNS Structure

  1. Hierarchical Organization

  • Root domain (.)

  • Top-level domains (TLDs)

  • Second-level domains

  • Subdomains

DNS Records

  1. Common Record Types

  • A Record (IPv4 address)

  • AAAA Record (IPv6 address)

  • CNAME (Canonical name)

  • MX (Mail exchanger)

  • TXT (Text records)

  • NS (Name server)

Resolution Process

  1. DNS Query Steps

  • Recursive resolution

  • Iterative queries

  • Caching mechanisms

  • Time-to-live (TTL)

References

  • RFC 1034 - Domain Names - Concepts and Facilities

  • RFC 1035 - Domain Names - Implementation and Specification