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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <!-- - Copyright (C) 2000-2021 Internet Systems Consortium, Inc. ("ISC") - - This Source Code Form is subject to the terms of the Mozilla Public - License, v. 2.0. If a copy of the MPL was not distributed with this - file, You can obtain one at http://mozilla.org/MPL/2.0/. --> <html lang="en"> <head> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> <title>Appendix�D.�BIND 9 DNS Library Support</title> <meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> <link rel="home" 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.ch11.html" title="Appendix�C.�General DNS Reference Information"> <link rel="next" href="Bv9ARM.ch13.html" title="Manual pages"> </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">Appendix�D.�BIND 9 DNS Library Support</th></tr> <tr> <td width="20%" align="left"> <a accesskey="p" href="Bv9ARM.ch11.html">Prev</a>�</td> <th width="60%" align="center">�</th> <td width="20%" align="right">�<a accesskey="n" href="Bv9ARM.ch13.html">Next</a> </td> </tr> </table> <hr> </div> <div class="appendix"> <div class="titlepage"><div><div><h1 class="title"> <a name="Bv9ARM.ch12"></a>BIND 9 DNS Library Support</h1></div></div></div> <div class="toc"> <p><b>Table of Contents</b></p> <dl class="toc"> <dt><span class="section"><a href="Bv9ARM.ch12.html#bind9.library">BIND 9 DNS Library Support</a></span></dt> <dd><dl> <dt><span class="section"><a href="Bv9ARM.ch12.html#id-1.13.2.5">Installation</a></span></dt> <dt><span class="section"><a href="Bv9ARM.ch12.html#id-1.13.2.6">Known Defects/Restrictions</a></span></dt> <dt><span class="section"><a href="Bv9ARM.ch12.html#id-1.13.2.7">The dns.conf File</a></span></dt> <dt><span class="section"><a href="Bv9ARM.ch12.html#id-1.13.2.8">Sample Applications</a></span></dt> <dt><span class="section"><a href="Bv9ARM.ch12.html#id-1.13.2.9">Library References</a></span></dt> </dl></dd> </dl> </div> <div class="section"> <div class="titlepage"><div><div><h2 class="title" style="clear: both"> <a name="bind9.library"></a>BIND 9 DNS Library Support</h2></div></div></div> <p> This version of BIND 9 "exports" its internal libraries so that they can be used by third-party applications more easily (we call them "export" libraries in this document). Certain library functions are altered from specific BIND-only behavior to more generic behavior when used by other applications; to enable this generic behavior, the calling program initializes the libraries by calling <span class="command"><strong>isc_lib_register()</strong></span>. </p> <p> In addition to DNS-related APIs that are used within BIND 9, the libraries provide the following features: </p> <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> <li class="listitem"><p> The "DNS client" module. This is a higher-level API that provides an interface to name resolution, single DNS transaction with a particular server, and dynamic update. Regarding name resolution, it supports advanced features such as DNSSEC validation and caching. This module supports both synchronous and asynchronous mode. </p></li> <li class="listitem"><p> The "IRS" (Information Retrieval System) library. It provides an interface to parse the traditional <code class="filename">resolv.conf</code> file and more advanced, DNS-specific configuration file for the rest of this package (see the description for the <code class="filename">dns.conf</code> file below). </p></li> <li class="listitem"><p> As part of the IRS library, the standard address-name mapping functions, <span class="command"><strong>getaddrinfo()</strong></span> and <span class="command"><strong>getnameinfo()</strong></span>, are provided. They use the DNSSEC-aware validating resolver backend, and could use other advanced features of the BIND 9 libraries such as caching. The <span class="command"><strong>getaddrinfo()</strong></span> function resolves both A and AAAA RRs concurrently when the address family is unspecified. </p></li> <li class="listitem"><p> An experimental framework to support other event libraries than BIND 9's internal event task system. </p></li> </ul></div> <div class="section"> <div class="titlepage"><div><div><h3 class="title"> <a name="id-1.13.2.5"></a>Installation</h3></div></div></div> <pre class="screen"> $ <strong class="userinput"><code>make install</code></strong> </pre> <p> Normal installation of BIND also installs library object and header files. Root privilege is normally required. </p> <p> To see how to build a custom application after the installation, see <code class="filename">lib/samples/Makefile-postinstall.in</code>. </p> </div> <div class="section"> <div class="titlepage"><div><div><h3 class="title"> <a name="id-1.13.2.6"></a>Known Defects/Restrictions</h3></div></div></div> <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> <li class="listitem"> <p> The "fixed" RRset order is not (currently) supported in the export library. To use "fixed" RRset order for, e.g., <span class="command"><strong>named</strong></span> while still building the export library even without the fixed-order support, build them separately: </p> <pre class="screen"> $ <strong class="userinput"><code>./configure --enable-fixed-rrset <em class="replaceable"><code>[other flags, but not --enable-exportlib]</code></em></code></strong> $ <strong class="userinput"><code>make</code></strong> $ <strong class="userinput"><code>./configure --enable-exportlib <em class="replaceable"><code>[other flags, but not --enable-fixed-rrset]</code></em></code></strong> $ <strong class="userinput"><code>cd lib/export</code></strong> $ <strong class="userinput"><code>make</code></strong> </pre> <p> </p> </li> <li class="listitem"><p> RFC 5011 is not supported in the validating stub resolver of the export library. In fact, it is not clear whether it should be: trust anchors would be a system-wide configuration which would be managed by an administrator, while the stub resolver is used by ordinary applications run by a normal user. </p></li> <li class="listitem"><p> Not all common <code class="filename">/etc/resolv.conf</code> options are supported in the IRS library. The only available options in this version are <span class="command"><strong>debug</strong></span> and <span class="command"><strong>ndots</strong></span>. </p></li> </ul></div> </div> <div class="section"> <div class="titlepage"><div><div><h3 class="title"> <a name="id-1.13.2.7"></a>The dns.conf File</h3></div></div></div> <p> The IRS library supports an "advanced" configuration file related to the DNS library, for configuration parameters that would be beyond the capability of the <code class="filename">resolv.conf</code> file. Specifically, it is intended to provide DNSSEC-related configuration parameters. By default the path to this configuration file is <code class="filename">/etc/dns.conf</code>. This module is very experimental and the configuration syntax or library interfaces may change in future versions. Currently, only the <span class="command"><strong>trusted-keys</strong></span> statement is supported, whose syntax is the same as the same statement in <code class="filename">named.conf</code>. (See <a class="xref" href="Bv9ARM.ch06.html#trusted-keys" title="trusted-keys Statement Grammar">the section called “<span class="command"><strong>trusted-keys</strong></span> Statement Grammar”</a> for details.) </p> </div> <div class="section"> <div class="titlepage"><div><div><h3 class="title"> <a name="id-1.13.2.8"></a>Sample Applications</h3></div></div></div> <p> Some sample application programs using this API are provided for reference. The following is a brief description of these applications. </p> <div class="section"> <div class="titlepage"><div><div><h4 class="title"> <a name="id-1.13.2.8.3"></a>sample: a simple stub resolver utility</h4></div></div></div> <p> This sends a query of a given name (of a given optional RR type) to a specified recursive server and prints the result as a list of RRs. It can also act as a validating stub resolver if a trust anchor is given via a set of command-line options. </p> <p> Usage: sample [options] server_address hostname </p> <p> Options and Arguments: </p> <div class="variablelist"><dl class="variablelist"> <dt><span class="term">-t RRtype</span></dt> <dd><p> specifies the RR type of the query. The default is the A RR. </p></dd> <dt><span class="term">[-a algorithm] [-e] -k keyname -K keystring</span></dt> <dd> <p> specifies a command-line DNS key to validate the answer. For example, to specify the following DNSKEY of example.com: </p> <div class="literallayout"><p><br> ��������������example.com.�3600�IN�DNSKEY�257�3�5�xxx<br> ������</p></div> <p> specify the options as follows: </p> <pre class="screen"> <strong class="userinput"><code>-e -k example.com -K "xxx"</code></strong> </pre> <p> -e means that this key is a zone's "key signing key" (also known as "secure entry point"). When -a is omitted rsasha1 is used by default. </p> </dd> <dt><span class="term">-s domain:alt_server_address</span></dt> <dd><p> specifies a separate recursive server address for the specific "domain". Example: -s example.com:2001:db8::1234 </p></dd> <dt><span class="term">server_address</span></dt> <dd><p> is an IP(v4/v6) address of the recursive server to which queries are sent. </p></dd> <dt><span class="term">hostname</span></dt> <dd><p> is the domain name for the query </p></dd> </dl></div> </div> <div class="section"> <div class="titlepage"><div><div><h4 class="title"> <a name="id-1.13.2.8.4"></a>sample-async: a simple stub resolver, working asynchronously</h4></div></div></div> <p> This is similar to "sample", but accepts a list of (query) domain names as a separate file and resolves the names asynchronously.</p> <p> Usage: sample-async [-s server_address] [-t RR_type] input_file</p> <p> Options and Arguments: </p> <div class="variablelist"><dl class="variablelist"> <dt><span class="term">-s server_address</span></dt> <dd> is an IPv4 address of the recursive server to which queries are sent. (IPv6 addresses are not supported in this implementation.) </dd> <dt><span class="term">-t RR_type</span></dt> <dd> specifies the RR type of the queries. The default is the A RR. </dd> <dt><span class="term">input_file</span></dt> <dd> is a list of domain names to be resolved; each line consists of a single domain name. For example: <div class="literallayout"><p><br> ������www.example.com<br> ������mx.example.net<br> ������ns.xxx.example<br> ������</p></div> </dd> </dl></div> </div> <div class="section"> <div class="titlepage"><div><div><h4 class="title"> <a name="id-1.13.2.8.5"></a>sample-request: a simple DNS transaction client</h4></div></div></div> <p> sends a query to a specified server, and prints the response with minimal processing. It does not act as a "stub resolver": it stops the processing once it gets any response from the server, whether it's a referral or an alias (CNAME or DNAME) that would require further queries to get the ultimate answer. In other words, this utility acts as a very simplified <span class="command"><strong>dig</strong></span>. </p> <p> Usage: sample-request [-t RRtype] server_address hostname </p> <p> Options and Arguments: </p> <div class="variablelist"><dl class="variablelist"> <dt><span class="term">-t RRtype</span></dt> <dd><p> specifies the RR type of the queries. The default is the A RR. </p></dd> <dt><span class="term">server_address</span></dt> <dd><p> is an IP(v4/v6) address of the recursive server to which the query is sent. </p></dd> <dt><span class="term">hostname</span></dt> <dd><p> is the domain name for the query </p></dd> </dl></div> </div> <div class="section"> <div class="titlepage"><div><div><h4 class="title"> <a name="id-1.13.2.8.6"></a>sample-gai: getaddrinfo() and getnameinfo() test code</h4></div></div></div> <p> is a test program to check <span class="command"><strong>getaddrinfo()</strong></span> and <span class="command"><strong>getnameinfo()</strong></span> behavior. It takes a host name as an argument, calls <span class="command"><strong>getaddrinfo()</strong></span> with the given host name, and calls <span class="command"><strong>getnameinfo()</strong></span> with the resulting IP addresses returned by <span class="command"><strong>getaddrinfo()</strong></span>. If the dns.conf file exists and defines a trust anchor, the underlying resolver acts as a validating resolver, and <span class="command"><strong>getaddrinfo()</strong></span>/<span class="command"><strong>getnameinfo()</strong></span> fails with an EAI_INSECUREDATA error when DNSSEC validation fails. </p> <p> Usage: sample-gai hostname </p> </div> <div class="section"> <div class="titlepage"><div><div><h4 class="title"> <a name="id-1.13.2.8.7"></a>sample-update: a simple dynamic update client program</h4></div></div></div> <p> accepts a single update command as a command-line argument, sends an update request message to the authoritative server, and shows the response from the server. In other words, this is a simplified <span class="command"><strong>nsupdate</strong></span>. </p> <p> Usage: sample-update [options] (add|delete) "update data" </p> <p> Options and Arguments: </p> <div class="variablelist"><dl class="variablelist"> <dt><span class="term">-a auth_server</span></dt> <dd><p> is an IP address of the authoritative server that has authority for the zone containing the update name. This should normally be the primary authoritative server that accepts dynamic updates. It can also be a secondary server that is configured to forward update requests to the primary server. </p></dd> <dt><span class="term">-k keyfile</span></dt> <dd><p> is a TSIG key file to secure the update transaction. The keyfile format is the same as that for the nsupdate utility. </p></dd> <dt><span class="term">-p prerequisite</span></dt> <dd><p> is a prerequisite for the update; only one prerequisite can be specified. The prerequisite format is the same as that accepted by the nsupdate utility. </p></dd> <dt><span class="term">-r recursive_server</span></dt> <dd><p> is an IP address of a recursive server that this utility uses. A recursive server may be necessary to identify the authoritative server address to which the update request is sent. </p></dd> <dt><span class="term">-z zonename</span></dt> <dd><p> is the domain name of the zone that it contains. </p></dd> <dt><span class="term">(add|delete)</span></dt> <dd><p> specifies the type of update operation. Either "add" or "delete" must be specified. </p></dd> <dt><span class="term">"update data"</span></dt> <dd><p> specifies the data to be updated. A typical example of the data looks like "name TTL RRtype RDATA". </p></dd> </dl></div> <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"> <h3 class="title">Note</h3> <p> In practice, either -a or -r must be specified. Others can be optional; the underlying library routine tries to identify the appropriate server and the zone name for the update. </p> </div> <p> Examples: assuming the primary authoritative server of the dynamic.example.com zone has an IPv6 address 2001:db8::1234, </p> <pre class="screen"> $ <strong class="userinput"><code>sample-update -a sample-update -k Kxxx.+nnn+mmmm.key add "foo.dynamic.example.com 30 IN A 192.168.2.1"</code></strong></pre> <p> adds an A RR for foo.dynamic.example.com using the given key. </p> <pre class="screen"> $ <strong class="userinput"><code>sample-update -a sample-update -k Kxxx.+nnn+mmmm.key delete "foo.dynamic.example.com 30 IN A"</code></strong></pre> <p> removes all A RRs for foo.dynamic.example.com using the given key. </p> <pre class="screen"> $ <strong class="userinput"><code>sample-update -a sample-update -k Kxxx.+nnn+mmmm.key delete "foo.dynamic.example.com"</code></strong></pre> <p> removes all RRs for foo.dynamic.example.com using the given key. </p> </div> <div class="section"> <div class="titlepage"><div><div><h4 class="title"> <a name="id-1.13.2.8.8"></a>nsprobe: domain/name server checker in terms of RFC 4074</h4></div></div></div> <p> checks a set of domains to ensure the name servers of the domains behave correctly in terms of RFC 4074. This is included in the set of sample programs to show how the export library can be used in a DNS-related application. </p> <p> Usage: nsprobe [-d] [-v [-v...]] [-c cache_address] [input_file] </p> <p> Options </p> <div class="variablelist"><dl class="variablelist"> <dt><span class="term">-d</span></dt> <dd><p> runs in "debug" mode. With this option, nsprobe dumps every RR it receives. </p></dd> <dt><span class="term">-v</span></dt> <dd><p> increases verbosity of other normal log messages. This can be specified multiple times. </p></dd> <dt><span class="term">-c cache_address</span></dt> <dd><p> specifies an IP address of a recursive (caching) name server. nsprobe uses this server to get the NS RRset of each domain and the A and/or AAAA RRsets for the name servers. The default value is 127.0.0.1. </p></dd> <dt><span class="term">input_file</span></dt> <dd><p> is a file name containing a list of domain (zone) names to be probed. when omitted the standard input is used. Each line of the input file specifies a single domain name, such as "example.com". In general, this domain name must be the apex name of some DNS zone, unlike normal "host names" such as "www.example.com". nsprobe first identifies the NS RRsets for the given domain name, and sends A and AAAA queries to these servers for some widely used names under the zone; specifically, adding "www" and "ftp" to the zone name. </p></dd> </dl></div> </div> </div> <div class="section"> <div class="titlepage"><div><div><h3 class="title"> <a name="id-1.13.2.9"></a>Library References</h3></div></div></div> <p> As of this writing, there is no formal "manual" for the libraries, except this document, header files (some of which provide pretty detailed explanations), and sample application programs. </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.ch11.html">Prev</a>�</td> <td width="20%" align="center">�</td> <td width="40%" align="right">�<a accesskey="n" href="Bv9ARM.ch13.html">Next</a> </td> </tr> <tr> <td width="40%" align="left" valign="top">Appendix�C.�General <acronym class="acronym">DNS</acronym> Reference Information�</td> <td width="20%" align="center"><a accesskey="h" href="Bv9ARM.html">Home</a></td> <td width="40%" align="right" valign="top">�Manual pages</td> </tr> </table> </div> <p xmlns:db="http://docbook.org/ns/docbook" style="text-align: center;">BIND 9.11.36 (Extended Support Version)</p> </body> </html>
