Bv9ARM.ch01.html revision aeb8fffc841865c3336383eadfd9987332a03286
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>Introduction </TITLE
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceNAME="GENERATOR"
027e89d47af308db4b41761ca9f847c026b63ec8Andreas GustafssonCONTENT="Modular DocBook HTML Stylesheet Version 1.41"><LINK
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceREL="PREVIOUS"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceTITLE="BIND Resource Requirements"
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f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="chapter"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>Chapter 1. Introduction </A
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>Table of Contents</B
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>Scope of Document</A
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>Organization of This Document</A
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>Conventions Used in This Document</A
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>Discussion of Domain Name System (<SPAN
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="acronym"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>) Basics and
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="acronym"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>The Internet Domain Name System (<SPAN
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="acronym"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>) consists of the syntax
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce to specify the names of entities in the Internet in a hierarchical
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce manner, the rules used for delegating authority over names, and the
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce system implementation that actually maps names to Internet
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce addresses. <SPAN
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="acronym"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce> data is maintained in a group of distributed
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce hierarchical databases.</P
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="sect1"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="sect1"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>1.1. Scope of Document</A
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>The Berkeley Internet Name Domain (<SPAN
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="acronym"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>) implements an
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce Internet nameserver for a number of operating systems. This
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce document provides basic information about the installation and
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce care of the Internet Software Consortium (<SPAN
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="acronym"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="acronym"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce software package for system administrators.</P
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="sect1"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="sect1"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>1.2. Organization of This Document</A
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>In this document, <I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="emphasis"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>Section 1</I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce the basic <SPAN
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="acronym"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="acronym"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce> concepts. <I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="emphasis"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>Section 2</I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce describes resource requirements for running <SPAN
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="acronym"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce environments. Information in <I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="emphasis"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>Section 3</I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="emphasis"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>task-oriented</I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce> in its presentation and is
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce organized functionally, to aid in the process of installing the
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="acronym"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce> 9 software. The task-oriented section is followed by
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="emphasis"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>Section 4</I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>, which contains more advanced
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce concepts that the system administrator may need for implementing
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce certain options. Section 5 describes the <SPAN
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="acronym"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce> 9 lightweight
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce resolver. The contents of <I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="emphasis"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>Section 6</I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce organized as in a reference manual to aid in the ongoing
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce maintenance of the software. <I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="emphasis"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>addresses security considerations, and
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="emphasis"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>Section 8</I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce> contains troubleshooting help. The
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce main body of the document is followed by several
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="emphasis"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>Appendices</I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce> which contain useful reference
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce information, such as a <I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="emphasis"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>Bibliography</I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce historic information related to <SPAN
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="acronym"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce> and the Domain Name
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="sect1"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="sect1"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>1.3. Conventions Used in This Document</A
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>In this document, we use the following general typographic
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce conventions:</P
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="informaltable"
aeb8fffc841865c3336383eadfd9987332a03286Andreas GustafssonCELLPADDING="3"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="CALSTABLE"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceVALIGN="MIDDLE"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="emphasis"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceVALIGN="MIDDLE"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="emphasis"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>We use the style:</I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceVALIGN="MIDDLE"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>a pathname, filename, URL, hostname,
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucemailing list name, or new term or concept</P
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceVALIGN="MIDDLE"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="filename"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceVALIGN="MIDDLE"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>literal user
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceVALIGN="MIDDLE"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="userinput"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>Fixed Width Bold</B
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceVALIGN="MIDDLE"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>variable user
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceVALIGN="MIDDLE"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="optional"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>Fixed Width Italic</SPAN
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceVALIGN="MIDDLE"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>program output</P
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceVALIGN="MIDDLE"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="computeroutput"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>Fixed Width Bold</TT
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>The following conventions are used in descriptions of the
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="acronym"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce> configuration file:<DIV
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="informaltable"
aeb8fffc841865c3336383eadfd9987332a03286Andreas GustafssonCELLPADDING="3"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="CALSTABLE"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceVALIGN="MIDDLE"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="emphasis"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceVALIGN="MIDDLE"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="emphasis"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>We use the style:</I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceVALIGN="MIDDLE"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceVALIGN="MIDDLE"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="literal"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>Sans Serif Bold</TT
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceVALIGN="MIDDLE"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>variables</P
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceVALIGN="MIDDLE"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="varname"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>Sans Serif Italic</TT
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceVALIGN="MIDDLE"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>"meta-syntactic"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceinformation (within brackets when optional)</P
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceVALIGN="MIDDLE"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="optional"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>Fixed Width Italic</SPAN
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceVALIGN="MIDDLE"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>Command line
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceVALIGN="MIDDLE"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="userinput"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>Fixed Width Bold</B
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceVALIGN="MIDDLE"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>Program output</P
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceVALIGN="MIDDLE"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="computeroutput"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>Fixed Width</TT
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceVALIGN="MIDDLE"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>Optional input</P
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceVALIGN="MIDDLE"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="optional"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>Text is enclosed in square brackets</SPAN
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="sect1"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="sect1"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceNAME="AEN121"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>1.4. Discussion of Domain Name System (<SPAN
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="acronym"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>) Basics and
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="acronym"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>The purpose of this document is to explain the installation
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceand basic upkeep of the <SPAN
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="acronym"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce> software package, and we begin by reviewing
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucethe fundamentals of the domain naming system as they relate to <SPAN
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="acronym"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="acronym"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce> consists of a <I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="emphasis"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>nameserver</I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce> (or "daemon")
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="command"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="command"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="acronym"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce> server runs in the background, servicing queries on a well
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceknown network port. The standard port for the User Datagram Protocol
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce(UDP) and Transmission Control Protocol (TCP), usually port 53,
5f09ce124cad9712a9675f17f83ddc915e734909Andreas Gustafssonis specified in <TT
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="filename"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="emphasis"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce> is a set of routines residing
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucein a system library that provides the interface that programs can
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceuse to access the domain name services.</P
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="sect2"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="sect2"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>1.4.1. Nameservers</A
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>A nameserver (NS) is a program that stores information about
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucenamed resources and responds to queries from programs called <I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="emphasis"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>resolvers</I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceact as client processes. The basic function of an NS is to provide
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceinformation about network objects by answering queries.</P
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>With the nameserver, the network can be broken into a hierarchy
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceof domains. The name space is organized as a tree according to organizational
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceor administrative boundaries. Each node of the tree, called a domain,
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceis given a label. The name of the domain is the concatenation of
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceall the labels of the domains from the root to the current domain.
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceThis is represented in written form as a string of labels listed
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucefrom right to left and separated by dots. A label need only be unique
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucewithin its domain. The whole name space is partitioned into areas
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="emphasis"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>, each starting at a domain and
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceextending down to the leaf domains or to domains where other zones
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucestart. Zones usually represent administrative boundaries. For example,
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucea domain name for a host at the company <I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="emphasis"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>Example, Inc.</I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="systemitem"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="systemitem"
56f1285ca5d97d3205b74c32dc4de1ea7b69fea1Michael Sawyer> is the top level domain to which
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="systemitem"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="systemitem"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>example</SPAN
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucea subdomain of <SPAN
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="systemitem"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="systemitem"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>ourhost</SPAN
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucename of the host.</P
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>The specifications for the domain nameserver are defined in
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucethe RFC 1034, RFC 1035 and RFC 974. These documents can be found
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="filename"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce> in 4.4BSD or are available
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucevia File Transfer Protocol (FTP) from
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceTARGET="_top"
56f1285ca5d97d3205b74c32dc4de1ea7b69fea1Michael Sawyeror via the Web at <A
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceTARGET="_top"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce(See Appendix C for complete information on finding and retrieving
56f1285ca5d97d3205b74c32dc4de1ea7b69fea1Michael SawyerRFCs.) It is also recommended that you read the related man pages:
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="command"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="command"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="sect2"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="sect2"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>1.4.2. Types of Zones</A
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>As we stated previously, a zone is a point of delegation in
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="acronym"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce> tree. A zone consists of those contiguous parts of the domain
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucetree for which a domain server has complete information and over which
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceit has authority. It contains all domain names from a certain point
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucedownward in the domain tree except those which are delegated to
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceother zones. A delegation point has one or more NS records in the
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceparent zone, which should be matched by equivalent NS records at
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucethe root of the delegated zone.</P
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>To properly operate a nameserver, it is important to understand
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucethe difference between a <I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="emphasis"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="emphasis"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>For instance, consider the <SPAN
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="systemitem"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucewhich includes names such as <SPAN
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="systemitem"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="systemitem"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucethough the <SPAN
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="systemitem"
56f1285ca5d97d3205b74c32dc4de1ea7b69fea1Michael Sawyerzone includes only delegations for the
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="systemitem"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="systemitem"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceA zone can map exactly to a single domain, but could also include
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceonly part of a domain, the rest of which could be delegated to other
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucenameservers. Every name in the <SPAN
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="acronym"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce> tree is a <I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="emphasis"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceeven if it is <I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="emphasis"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>, that is, has no <I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="emphasis"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>subdomains</I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceEvery subdomain is a domain and every domain except the root is
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucealso a subdomain. The terminology is not intuitive and we suggest
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucethat you read RFCs 1033, 1034 and 1035 to gain a complete understanding
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceof this difficult and subtle topic.</P
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>Though <SPAN
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="acronym"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce> is a Domain Nameserver, it deals primarily in
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceterms of zones. The master and slave declarations in the <TT
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="filename"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucespecify zones, not domains. When you ask some other site if it is willing
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceto be a slave server for your <I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="emphasis"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceactually asking for slave service for some collection of zones.</P
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>Each zone will have one <I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="emphasis"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>primary master</I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="emphasis"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>) server which loads the zone
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucecontents from some local file edited by humans or perhaps generated
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucemechanically from some other local file which is edited by humans.
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceThere there will be some number of <I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="emphasis"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="emphasis"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>secondary) </I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>servers, which load the zone
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucecontents using the <SPAN
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="acronym"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce> protocol (that is, the secondary servers
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucewill contact the primary and fetch the zone data using TCP). This
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceset of servers — the primary and all of its secondaries — should be
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucelisted in the NS records in the parent zone and will constitute a <I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="emphasis"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>delegation</I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceThis set of servers must also be listed in the zone file itself,
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceusually under the <B
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="command"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce> name which indicates the <I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="emphasis"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="emphasis"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce> of the current zone.
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceYou can list servers in the zone's top-level <B
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="command"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucerecords that are not in the parent's NS delegation, but you cannot
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucelist servers in the parent's delegation that are not present in
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucethe zone's <B
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="command"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>Any servers listed in the NS records must be configured as <I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="emphasis"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>authoritative</I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucethe zone. A server is authoritative for a zone when it has been
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceconfigured to answer questions for that zone with authority, which
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceit does by setting the "authoritative answer" (AA) bit in reply
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucepackets. A server may be authoritative for more than one zone. The
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceauthoritative data for a zone is composed of all of the Resource
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceRecords (RRs) — the data associated with names in a tree-structured
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucename space — attached to all of the nodes from the top node of the
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucezone down to leaf nodes or nodes above cuts around the bottom edge
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceof the zone.</P
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>Adding a zone as a type master or type slave will tell the
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceserver to answer questions for the zone authoritatively. If the
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceserver is able to load the zone into memory without any errors it
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucewill set the AA bit when it replies to queries for the zone. See
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceRFCs 1034 and 1035 for more information about the AA bit.</P
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="sect2"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="sect2"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>1.4.3. Servers</A
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="acronym"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce> server can be master for some zones and slave for others
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceor can be only a master, or only a slave, or can serve no zones
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceand just answer queries via its <I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="emphasis"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceservers are often also called <I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="emphasis"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>primaries</I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceslave servers are often also called <I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="emphasis"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>secondaries</I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceBoth master/primary and slave/secondary servers are authoritative
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucefor a zone.</P
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>All servers keep data in their cache until the data expires,
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucebased on a Time To Live (TTL) field which is maintained for all
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceresource records.</P
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="sect3"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="sect3"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>1.4.3.1. Master Server</A
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="emphasis"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>primary master server</I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce> is the ultimate
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucesource of information about a domain. The primary master is an authoritative
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceserver configured to be the source of zone transfer for one or more
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucesecondary servers. The primary master server obtains data for the
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucezone from a file on disk.</P
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="sect3"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="sect3"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>1.4.3.2. Slave Server</A
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="emphasis"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>slave server</I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>, also called a <I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="emphasis"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>, is an authoritative server that uses zone transfers from
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucethe primary master server to retrieve the zone data. Optionally,
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucethe slave server obtains zone data from a cache on disk. Slave servers
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceprovide necessary redundancy. All secondary/slave servers are named
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucein the NS RRs for the zone.</P
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="sect3"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="sect3"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>1.4.3.3. Caching Only Server</A
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>Some servers are <I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="emphasis"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>caching only servers</I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceThis means that the server caches the information that it receives
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceand uses it until the data expires. A caching only server is a server
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucethat is not authoritative for any zone. This server services queries
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceand asks other servers, who have the authority, for the information
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="sect3"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="sect3"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>1.4.3.4. Forwarding Server</A
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>Instead of interacting with the nameservers for the root and
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceother domains, a <I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="emphasis"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>forwarding server</I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce> always forwards
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucequeries it cannot satisfy from its authoritative data or cache to
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucea fixed list of other servers. The forwarded queries are also known
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="emphasis"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>recursive queries</I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>, the same type as a client would
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucesend to a server. There may be one or more servers forwarded to,
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceand they are queried in turn until the list is exhausted or an answer
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceis found. A forwarding server is typically used when you do not
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucewish all the servers at a given site to interact with the rest of
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucethe Internet servers. A typical scenario would involve a number
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceof internal <SPAN
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="acronym"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce> servers and an Internet firewall. Servers unable
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceto pass packets through the firewall would forward to the server
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucethat can do it, and that server would query the Internet <SPAN
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="acronym"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceon the internal server's behalf. An added benefit of using the forwarding
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucefeature is that the central machine develops a much more complete
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucecache of information that all the workstations can take advantage
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>There is no prohibition against declaring a server to be a
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceforwarder even though it has master and/or slave zones as well;
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucethe effect will still be that anything in the local server's cache
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceor zones will be answered, and anything else will be forwarded using
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucethe forwarders list.</P
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="sect3"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="sect3"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>1.4.3.5. Stealth Server</A
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="emphasis"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce>stealth server</I
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce> is a server that answers
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceauthoritatively for a zone, but is not listed in that zone's NS
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucerecords. Stealth servers can be used as a way to centralize distribution
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceof a zone, without having to edit the zone on a remote nameserver.
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceWhere the master file for a zone resides on a stealth server in
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucethis way, it is often referred to as a "hidden primary" configuration.
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceStealth servers can also be a way to keep a local copy of a zone
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucefor rapid access to the zone's records, even if all "official" nameservers
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucefor the zone are inaccessible.</P
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="NAVFOOTER"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCELLPADDING="0"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCELLSPACING="0"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceALIGN="center"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceALIGN="right"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceALIGN="center"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceALIGN="right"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric LuceCLASS="acronym"
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce> Resource Requirements</TD