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diff --git a/contrib/bind9/doc/arm/Bv9ARM.ch01.html b/contrib/bind9/doc/arm/Bv9ARM.ch01.html deleted file mode 100644 index 37f1eec39ab75..0000000000000 --- a/contrib/bind9/doc/arm/Bv9ARM.ch01.html +++ /dev/null @@ -1,412 +0,0 @@ -<!-- - - Copyright (C) 2004, 2005 Internet Systems Consortium, Inc. ("ISC") - - Copyright (C) 2000-2003 Internet Software Consortium. - - - - Permission to use, copy, modify, and distribute this software for any - - purpose with or without fee is hereby granted, provided that the above - - copyright notice and this permission notice appear in all copies. - - - - THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH - - REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY - - AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, - - INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM - - LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE - - OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR - - PERFORMANCE OF THIS SOFTWARE. ---> -<!-- $Id: Bv9ARM.ch01.html,v 1.12.2.2.8.9 2005/10/13 02:33:58 marka Exp $ --> -<html> -<head> -<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> -<title>Chapter 1. Introduction </title> -<meta name="generator" content="DocBook XSL Stylesheets V1.69.1"> -<link rel="start" href="Bv9ARM.html" title="BIND 9 Administrator Reference Manual"> -<link rel="up" href="Bv9ARM.html" title="BIND 9 Administrator Reference Manual"> -<link rel="prev" href="Bv9ARM.html" title="BIND 9 Administrator Reference Manual"> -<link rel="next" href="Bv9ARM.ch02.html" title="Chapter 2. BIND Resource Requirements"> -</head> -<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> -<div class="navheader"> -<table width="100%" summary="Navigation header"> -<tr><th colspan="3" align="center">Chapter 1. Introduction </th></tr> -<tr> -<td width="20%" align="left"> -<a accesskey="p" href="Bv9ARM.html">Prev</a> </td> -<th width="60%" align="center"> </th> -<td width="20%" align="right"> <a accesskey="n" href="Bv9ARM.ch02.html">Next</a> -</td> -</tr> -</table> -<hr> -</div> -<div class="chapter" lang="en"> -<div class="titlepage"><div><div><h2 class="title"> -<a name="Bv9ARM.ch01"></a>Chapter 1. Introduction </h2></div></div></div> -<div class="toc"> -<p><b>Table of Contents</b></p> -<dl> -<dt><span class="sect1"><a href="Bv9ARM.ch01.html#id2545879">Scope of Document</a></span></dt> -<dt><span class="sect1"><a href="Bv9ARM.ch01.html#id2545905">Organization of This Document</a></span></dt> -<dt><span class="sect1"><a href="Bv9ARM.ch01.html#id2545976">Conventions Used in This Document</a></span></dt> -<dt><span class="sect1"><a href="Bv9ARM.ch01.html#id2546234">The Domain Name System (<span class="acronym">DNS</span>)</a></span></dt> -<dd><dl> -<dt><span class="sect2"><a href="Bv9ARM.ch01.html#id2546254">DNS Fundamentals</a></span></dt> -<dt><span class="sect2"><a href="Bv9ARM.ch01.html#id2544105">Domains and Domain Names</a></span></dt> -<dt><span class="sect2"><a href="Bv9ARM.ch01.html#id2546579">Zones</a></span></dt> -<dt><span class="sect2"><a href="Bv9ARM.ch01.html#id2546653">Authoritative Name Servers</a></span></dt> -<dt><span class="sect2"><a href="Bv9ARM.ch01.html#id2546950">Caching Name Servers</a></span></dt> -<dt><span class="sect2"><a href="Bv9ARM.ch01.html#id2547076">Name Servers in Multiple Roles</a></span></dt> -</dl></dd> -</dl> -</div> -<p>The Internet Domain Name System (<span class="acronym">DNS</span>) consists of the syntax - to specify the names of entities in the Internet in a hierarchical - manner, the rules used for delegating authority over names, and the - system implementation that actually maps names to Internet - addresses. <span class="acronym">DNS</span> data is maintained in a group of distributed - hierarchical databases.</p> -<div class="sect1" lang="en"> -<div class="titlepage"><div><div><h2 class="title" style="clear: both"> -<a name="id2545879"></a>Scope of Document</h2></div></div></div> -<p>The Berkeley Internet Name Domain (<span class="acronym">BIND</span>) implements an - domain name server for a number of operating systems. This - document provides basic information about the installation and - care of the Internet Software Consortium (<span class="acronym">ISC</span>) - <span class="acronym">BIND</span> version 9 software package for system - administrators.</p> -<p>This version of the manual corresponds to BIND version 9.3.</p> -</div> -<div class="sect1" lang="en"> -<div class="titlepage"><div><div><h2 class="title" style="clear: both"> -<a name="id2545905"></a>Organization of This Document</h2></div></div></div> -<p>In this document, <span class="emphasis"><em>Section 1</em></span> introduces - the basic <span class="acronym">DNS</span> and <span class="acronym">BIND</span> concepts. <span class="emphasis"><em>Section 2</em></span> - describes resource requirements for running <span class="acronym">BIND</span> in various - environments. Information in <span class="emphasis"><em>Section 3</em></span> is - <span class="emphasis"><em>task-oriented</em></span> in its presentation and is - organized functionally, to aid in the process of installing the - <span class="acronym">BIND</span> 9 software. The task-oriented section is followed by - <span class="emphasis"><em>Section 4</em></span>, which contains more advanced - concepts that the system administrator may need for implementing - certain options. <span class="emphasis"><em>Section 5</em></span> - describes the <span class="acronym">BIND</span> 9 lightweight - resolver. The contents of <span class="emphasis"><em>Section 6</em></span> are - organized as in a reference manual to aid in the ongoing - maintenance of the software. <span class="emphasis"><em>Section 7 - </em></span>addresses security considerations, and - <span class="emphasis"><em>Section 8</em></span> contains troubleshooting help. The - main body of the document is followed by several - <span class="emphasis"><em>Appendices</em></span> which contain useful reference - information, such as a <span class="emphasis"><em>Bibliography</em></span> and - historic information related to <span class="acronym">BIND</span> and the Domain Name - System.</p> -</div> -<div class="sect1" lang="en"> -<div class="titlepage"><div><div><h2 class="title" style="clear: both"> -<a name="id2545976"></a>Conventions Used in This Document</h2></div></div></div> -<p>In this document, we use the following general typographic - conventions:</p> -<div class="informaltable"><table border="1"> -<colgroup> -<col> -<col> -</colgroup> -<tbody> -<tr> -<td> -<p><span class="emphasis"><em>To -describe:</em></span></p> -</td> -<td> -<p><span class="emphasis"><em>We use the style:</em></span></p> -</td> -</tr> -<tr> -<td> -<p>a pathname, filename, URL, hostname, -mailing list name, or new term or concept</p> -</td> -<td><p><code class="filename">Fixed width</code></p></td> -</tr> -<tr> -<td><p>literal user -input</p></td> -<td><p><strong class="userinput"><code>Fixed Width Bold</code></strong></p></td> -</tr> -<tr> -<td><p>program output</p></td> -<td><p><code class="computeroutput">Fixed Width</code></p></td> -</tr> -</tbody> -</table></div> -<p>The following conventions are used in descriptions of the -<span class="acronym">BIND</span> configuration file:</p> -<div class="informaltable"><table border="1"> -<colgroup> -<col> -<col> -</colgroup> -<tbody> -<tr> -<td><p><span class="emphasis"><em>To -describe:</em></span></p></td> -<td><p><span class="emphasis"><em>We use the style:</em></span></p></td> -</tr> -<tr> -<td><p>keywords</p></td> -<td><p><code class="literal">Fixed Width</code></p></td> -</tr> -<tr> -<td><p>variables</p></td> -<td><p><code class="varname">Fixed Width</code></p></td> -</tr> -<tr> -<td><p>Optional input</p></td> -<td><p>[<span class="optional">Text is enclosed in square brackets</span>]</p></td> -</tr> -</tbody> -</table></div> -</div> -<div class="sect1" lang="en"> -<div class="titlepage"><div><div><h2 class="title" style="clear: both"> -<a name="id2546234"></a>The Domain Name System (<span class="acronym">DNS</span>)</h2></div></div></div> -<p>The purpose of this document is to explain the installation -and upkeep of the <span class="acronym">BIND</span> software package, and we -begin by reviewing the fundamentals of the Domain Name System -(<span class="acronym">DNS</span>) as they relate to <span class="acronym">BIND</span>. -</p> -<div class="sect2" lang="en"> -<div class="titlepage"><div><div><h3 class="title"> -<a name="id2546254"></a>DNS Fundamentals</h3></div></div></div> -<p>The Domain Name System (DNS) is the hierarchical, distributed -database. It stores information for mapping Internet host names to IP -addresses and vice versa, mail routing information, and other data -used by Internet applications.</p> -<p>Clients look up information in the DNS by calling a -<span class="emphasis"><em>resolver</em></span> library, which sends queries to one or -more <span class="emphasis"><em>name servers</em></span> and interprets the responses. -The <span class="acronym">BIND</span> 9 software distribution contains a -name server, <span><strong class="command">named</strong></span>, and two resolver -libraries, <span><strong class="command">liblwres</strong></span> and <span><strong class="command">libbind</strong></span>. -</p> -</div> -<div class="sect2" lang="en"> -<div class="titlepage"><div><div><h3 class="title"> -<a name="id2544105"></a>Domains and Domain Names</h3></div></div></div> -<p>The data stored in the DNS is identified by <span class="emphasis"><em>domain -names</em></span> that are organized as a tree according to -organizational or administrative boundaries. Each node of the tree, -called a <span class="emphasis"><em>domain</em></span>, is given a label. The domain name of the -node is the concatenation of all the labels on the path from the -node to the <span class="emphasis"><em>root</em></span> node. This is represented -in written form as a string of labels listed from right to left and -separated by dots. A label need only be unique within its parent -domain.</p> -<p>For example, a domain name for a host at the -company <span class="emphasis"><em>Example, Inc.</em></span> could be -<code class="literal">mail.example.com</code>, -where <code class="literal">com</code> is the -top level domain to which -<code class="literal">ourhost.example.com</code> belongs, -<code class="literal">example</code> is -a subdomain of <code class="literal">com</code>, and -<code class="literal">ourhost</code> is the -name of the host.</p> -<p>For administrative purposes, the name space is partitioned into -areas called <span class="emphasis"><em>zones</em></span>, each starting at a node and -extending down to the leaf nodes or to nodes where other zones start. -The data for each zone is stored in a <span class="emphasis"><em>name -server</em></span>, which answers queries about the zone using the -<span class="emphasis"><em>DNS protocol</em></span>. -</p> -<p>The data associated with each domain name is stored in the -form of <span class="emphasis"><em>resource records</em></span> (<span class="acronym">RR</span>s). -Some of the supported resource record types are described in -<a href="Bv9ARM.ch06.html#types_of_resource_records_and_when_to_use_them" title="Types of Resource Records and When to Use Them">the section called “Types of Resource Records and When to Use Them”</a>.</p> -<p>For more detailed information about the design of the DNS and -the DNS protocol, please refer to the standards documents listed in -<a href="Bv9ARM.ch09.html#rfcs" title="Request for Comments (RFCs)">the section called “Request for Comments (RFCs)”</a>.</p> -</div> -<div class="sect2" lang="en"> -<div class="titlepage"><div><div><h3 class="title"> -<a name="id2546579"></a>Zones</h3></div></div></div> -<p>To properly operate a name server, it is important to understand -the difference between a <span class="emphasis"><em>zone</em></span> -and a <span class="emphasis"><em>domain</em></span>.</p> -<p>As we stated previously, a zone is a point of delegation in -the <span class="acronym">DNS</span> tree. A zone consists of -those contiguous parts of the domain -tree for which a name server has complete information and over which -it has authority. It contains all domain names from a certain point -downward in the domain tree except those which are delegated to -other zones. A delegation point is marked by one or more -<span class="emphasis"><em>NS records</em></span> in the -parent zone, which should be matched by equivalent NS records at -the root of the delegated zone.</p> -<p>For instance, consider the <code class="literal">example.com</code> -domain which includes names -such as <code class="literal">host.aaa.example.com</code> and -<code class="literal">host.bbb.example.com</code> even though -the <code class="literal">example.com</code> zone includes -only delegations for the <code class="literal">aaa.example.com</code> and -<code class="literal">bbb.example.com</code> zones. A zone can map -exactly to a single domain, but could also include only part of a -domain, the rest of which could be delegated to other -name servers. Every name in the <span class="acronym">DNS</span> tree is a -<span class="emphasis"><em>domain</em></span>, even if it is -<span class="emphasis"><em>terminal</em></span>, that is, has no -<span class="emphasis"><em>subdomains</em></span>. Every subdomain is a domain and -every domain except the root is also a subdomain. The terminology is -not intuitive and we suggest that you read RFCs 1033, 1034 and 1035 to -gain a complete understanding of this difficult and subtle -topic.</p> -<p>Though <span class="acronym">BIND</span> is called a "domain name server", -it deals primarily in terms of zones. The master and slave -declarations in the <code class="filename">named.conf</code> file specify -zones, not domains. When you ask some other site if it is willing to -be a slave server for your <span class="emphasis"><em>domain</em></span>, you are -actually asking for slave service for some collection of zones.</p> -</div> -<div class="sect2" lang="en"> -<div class="titlepage"><div><div><h3 class="title"> -<a name="id2546653"></a>Authoritative Name Servers</h3></div></div></div> -<p>Each zone is served by at least -one <span class="emphasis"><em>authoritative name server</em></span>, -which contains the complete data for the zone. -To make the DNS tolerant of server and network failures, -most zones have two or more authoritative servers. -</p> -<p>Responses from authoritative servers have the "authoritative -answer" (AA) bit set in the response packets. This makes them -easy to identify when debugging DNS configurations using tools like -<span><strong class="command">dig</strong></span> (<a href="Bv9ARM.ch03.html#diagnostic_tools" title="Diagnostic Tools">the section called “Diagnostic Tools”</a>).</p> -<div class="sect3" lang="en"> -<div class="titlepage"><div><div><h4 class="title"> -<a name="id2546676"></a>The Primary Master</h4></div></div></div> -<p> -The authoritative server where the master copy of the zone data is maintained is -called the <span class="emphasis"><em>primary master</em></span> server, or simply the -<span class="emphasis"><em>primary</em></span>. It loads the zone contents from some -local file edited by humans or perhaps generated mechanically from -some other local file which is edited by humans. This file is called -the <span class="emphasis"><em>zone file</em></span> or <span class="emphasis"><em>master file</em></span>.</p> -</div> -<div class="sect3" lang="en"> -<div class="titlepage"><div><div><h4 class="title"> -<a name="id2546902"></a>Slave Servers</h4></div></div></div> -<p>The other authoritative servers, the <span class="emphasis"><em>slave</em></span> -servers (also known as <span class="emphasis"><em>secondary</em></span> servers) load -the zone contents from another server using a replication process -known as a <span class="emphasis"><em>zone transfer</em></span>. Typically the data are -transferred directly from the primary master, but it is also possible -to transfer it from another slave. In other words, a slave server -may itself act as a master to a subordinate slave server.</p> -</div> -<div class="sect3" lang="en"> -<div class="titlepage"><div><div><h4 class="title"> -<a name="id2546921"></a>Stealth Servers</h4></div></div></div> -<p>Usually all of the zone's authoritative servers are listed in -NS records in the parent zone. These NS records constitute -a <span class="emphasis"><em>delegation</em></span> of the zone from the parent. -The authoritative servers are also listed in the zone file itself, -at the <span class="emphasis"><em>top level</em></span> or <span class="emphasis"><em>apex</em></span> -of the zone. You can list servers in the zone's top-level NS -records that are not in the parent's NS delegation, but you cannot -list servers in the parent's delegation that are not present at -the zone's top level.</p> -<p>A <span class="emphasis"><em>stealth server</em></span> is a server that is -authoritative for a zone but is not listed in that zone's NS -records. Stealth servers can be used for keeping a local copy of a -zone to speed up access to the zone's records or to make sure that the -zone is available even if all the "official" servers for the zone are -inaccessible.</p> -<p>A configuration where the primary master server itself is a -stealth server is often referred to as a "hidden primary" -configuration. One use for this configuration is when the primary master -is behind a firewall and therefore unable to communicate directly -with the outside world.</p> -</div> -</div> -<div class="sect2" lang="en"> -<div class="titlepage"><div><div><h3 class="title"> -<a name="id2546950"></a>Caching Name Servers</h3></div></div></div> -<p>The resolver libraries provided by most operating systems are -<span class="emphasis"><em>stub resolvers</em></span>, meaning that they are not capable of -performing the full DNS resolution process by themselves by talking -directly to the authoritative servers. Instead, they rely on a local -name server to perform the resolution on their behalf. Such a server -is called a <span class="emphasis"><em>recursive</em></span> name server; it performs -<span class="emphasis"><em>recursive lookups</em></span> for local clients.</p> -<p>To improve performance, recursive servers cache the results of -the lookups they perform. Since the processes of recursion and -caching are intimately connected, the terms -<span class="emphasis"><em>recursive server</em></span> and -<span class="emphasis"><em>caching server</em></span> are often used synonymously.</p> -<p>The length of time for which a record may be retained in -in the cache of a caching name server is controlled by the -Time To Live (TTL) field associated with each resource record. -</p> -<div class="sect3" lang="en"> -<div class="titlepage"><div><div><h4 class="title"> -<a name="id2547050"></a>Forwarding</h4></div></div></div> -<p>Even a caching name server does not necessarily perform -the complete recursive lookup itself. Instead, it can -<span class="emphasis"><em>forward</em></span> some or all of the queries -that it cannot satisfy from its cache to another caching name server, -commonly referred to as a <span class="emphasis"><em>forwarder</em></span>. -</p> -<p>There may be one or more forwarders, -and they are queried in turn until the list is exhausted or an answer -is found. Forwarders are typically used when you do not -wish all the servers at a given site to interact directly with the rest of -the Internet servers. A typical scenario would involve a number -of internal <span class="acronym">DNS</span> servers and an Internet firewall. Servers unable -to pass packets through the firewall would forward to the server -that can do it, and that server would query the Internet <span class="acronym">DNS</span> servers -on the internal server's behalf. An added benefit of using the forwarding -feature is that the central machine develops a much more complete -cache of information that all the clients can take advantage -of.</p> -</div> -</div> -<div class="sect2" lang="en"> -<div class="titlepage"><div><div><h3 class="title"> -<a name="id2547076"></a>Name Servers in Multiple Roles</h3></div></div></div> -<p>The <span class="acronym">BIND</span> name server can simultaneously act as -a master for some zones, a slave for other zones, and as a caching -(recursive) server for a set of local clients.</p> -<p>However, since the functions of authoritative name service -and caching/recursive name service are logically separate, it is -often advantageous to run them on separate server machines. - -A server that only provides authoritative name service -(an <span class="emphasis"><em>authoritative-only</em></span> server) can run with -recursion disabled, improving reliability and security. - -A server that is not authoritative for any zones and only provides -recursive service to local -clients (a <span class="emphasis"><em>caching-only</em></span> server) -does not need to be reachable from the Internet at large and can -be placed inside a firewall.</p> -</div> -</div> -</div> -<div class="navfooter"> -<hr> -<table width="100%" summary="Navigation footer"> -<tr> -<td width="40%" align="left"> -<a accesskey="p" href="Bv9ARM.html">Prev</a> </td> -<td width="20%" align="center"> </td> -<td width="40%" align="right"> <a accesskey="n" href="Bv9ARM.ch02.html">Next</a> -</td> -</tr> -<tr> -<td width="40%" align="left" valign="top">BIND 9 Administrator Reference Manual </td> -<td width="20%" align="center"><a accesskey="h" href="Bv9ARM.html">Home</a></td> -<td width="40%" align="right" valign="top"> Chapter 2. <span class="acronym">BIND</span> Resource Requirements</td> -</tr> -</table> -</div> -</body> -</html> |