《NetBSD指南-25.1.4.Delegation》未完成

[leo]

使用NS记录, 一个域名树某点以下的DNS命名空间的部分权限可以被委托, 更深层的子部分也被委托. 在这里domain和zone的区别就很重要了. 在DNS里的任何名称被称为domain, 并且用于这个名称及树内其下的所有附属。 zone的分界线更窄了，并且由委托定义. 一个zone起始于一个委托(或起始于根), 并包含了domain中起始点以下的所有名称, 除非后来又重新进行了委托。

This distinction is important for implementation - a zone is a single administrative entity (with a single SOA record), and all data for the zone is referred to by a single file, called a zone file. A zone file may contain more than one period-separated level of the namespace tree, if desired, by including periods in the names in that zone file. In order to simplify administration and prevent overly-large zone files, it is quite legal for a DNS server to delegate to itself, splitting the domain into several zones kept on the same server.