Understand DNS

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Updated:October 23, 2025
Document ID:225283

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    Introduction

    This document describes the Domain Name System (DNS) and explains its role in network communications.

    What is the Domain Name System (DNS)?

    The Domain Name System (DNS) serves as a crucial component of the internet. DNS enables users to access websites, send emails, and perform other internet activities by directing requests to the correct locations.

    Think of the DNS as the internet's phone book. In the same way that a phone book keeps an index of phone numbers, DNS keeps an index of IP addresses for websites. IP addresses are computer-readable combinations of numbers that act as the authoritative address of websites. Every resource on the internet has an IP address. Humans cannot efficiently remember all numeric IP addresses. DNS allows users to connect to computer systems globally without the need to memorize or recall these numeric addresses.

    Revision History

    Revision Publish Date Comments
    1.0
    23-Oct-2025
    Initial Release
    TAC Authored

    Contributed by Cisco Engineers

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