Domain Name System/zh

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DNS（域名系统）是用于将字母数字域名转化为互联网协议数字的系统。简单地说，DNS将输入在网络浏览器地址栏中的名称转化为IP地址。^[1]

概述[edit | edit source]

DNS由许多服务器和数据库组成，通过在各种高速缓存存储器中进行一系列查找，将域名配置成IP地址。域名系统是一个分层排列的分布式数据库；其目的是在互联网服务（网络、电子邮件等）和用于唯一标识互联网上任何一台给定机器的数字地址（IP地址）之间提供一个抽象层。DNS各种信息与域名结合起来，最重要的是，将对于人类而言有意义的域名转化为可以定位指定目标的数字标识。

DNS的工作原理是什么？[edit | edit source]

DNS使人们能够将域名以有意义的方式分配给互联网资源以及用户，而与实体的位置无关。因此，即使是对于移动设备而言，“WWW”超链接也得以保持一致。人们通过域名更加容易记住一个地址，但是连接到互联网时，这个域名需要被转化为相应的数字形式，即IP格式。^[2]

互联网中的协调由一个复杂的授权根系统，即顶级域（TLD），以及DNS和其他负责托管单个域信息的小型名称服务器进行维护。对于每个域而言，DNS都通过映射域名并将之指定给IP地址来分担责任，反之亦然。这是通过已经指定给每个域的授权名称服务器来完成的。每个授权名称服务器负责其自身的特定域，但是它有权将新的授权名称服务器分配给它的子域。DNS能够存储各种类型的信息，甚至是某个特定域的电子邮件服务器列表。DNS作为能够确保互联网功能正常的核心元素，它的作用是通过其基于关键字的分布式重定向服务来实现的。

但是，DNS不包括安全扩展，而是被开发为域名系统安全扩展（DNSSEC）。

The Structure of a DNS[edit | edit source]

The Domain Name System presents the following structure:

Domain space name: represented by tree of domain names with nodes and leaves ^[3]
Domain name syntax: rules include in standards like RFC 1035, RFC 1123, and RFC 2181
Name server
Domain names Internationalized
DNS resolver: initiates the queries will finally lead to the complete translation (resolution) of the information.

DNS Services[edit | edit source]

These types of services include:

Managing the DNS
1. By means of powerful, secure and complete tools and DNS administration options such as Manage A records or MX records
2. By means of controlling and managing the traffic
Hosting the DNS
1. Efficient DNS resolution
Location DNS services: to ease visitors' work, increase visitors' satisfaction and strengthen the relationship with all visitors.^[4]

Recent developments[edit | edit source]

In 2012, an IETF draft proposal, called "DNS Extension for Autonomous Internet (AIP)," was written by three Chinese technologists suggesting a method of operating alternate DNS root servers within national boundaries using gateways for translation. All DNS requests would carry an additional TLD, in order to designate that the requests were being sent to an alternate root.

Domain node “www.yahoo.com” in network B is expressed as “www.yahoo.com.B” for its external domain name.

The proposal would allow greater governmental control over the Internet.^[5]