100 lines
4.1 KiB
XML
100 lines
4.1 KiB
XML
<!--
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- Copyright (C) Internet Systems Consortium, Inc. ("ISC")
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-
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- This Source Code Form is subject to the terms of the Mozilla Public
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- License, v. 2.0. If a copy of the MPL was not distributed with this
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- file, You can obtain one at http://mozilla.org/MPL/2.0/.
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-
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- See the COPYRIGHT file distributed with this work for additional
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- information regarding copyright ownership.
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-->
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<!-- Converted by db4-upgrade version 1.0 -->
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<section xmlns:db="http://docbook.org/ns/docbook" version="5.0" xml:id="dyndb-info"><info><title>Dynamic Database (DynDB)</title></info>
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<para>
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Dynamic Database, or DynDB, is an extension to BIND 9 which, like DLZ
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(see <xref linkend="dlz-info"/>), allows zone data to be
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retrieved from an external database. Unlike DLZ, a DynDB module
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provides a full-featured BIND zone database interface. Where
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DLZ translates DNS queries into real-time database lookups,
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resulting in relatively poor query performance, and is unable
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to handle DNSSEC-signed data due to its limited API, a DynDB
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module can pre-load an in-memory database from the external
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data source, providing the same performance and functionality
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as zones served natively by BIND.
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</para>
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<para>
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A DynDB module supporting LDAP has been created by Red Hat
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and is available from
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<link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="https://pagure.io/bind-dyndb-ldap">https://pagure.io/bind-dyndb-ldap</link>.
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</para>
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<para>
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A sample DynDB module for testing and developer guidance
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is included with the BIND source code, in the directory
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<filename>bin/tests/system/dyndb/driver</filename>.
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</para>
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<section><info><title>Configuring DynDB</title></info>
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<para>
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A DynDB database is configured with a <command>dyndb</command>
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statement in <filename>named.conf</filename>:
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</para>
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<screen>
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dyndb example "driver.so" {
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<replaceable>parameters</replaceable>
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};
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</screen>
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<para>
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The file <filename>driver.so</filename> is a DynDB module which
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implements the full DNS database API. Multiple
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<command>dyndb</command> statements can be specified, to load
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different drivers or multiple instances of the same driver.
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Zones provided by a DynDB module are added to the view's zone
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table, and are treated as normal authoritative zones when BIND
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responds to queries. Zone configuration is handled internally
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by the DynDB module.
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</para>
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<para>
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The <replaceable>parameters</replaceable> are passed as an opaque
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string to the DynDB module's initialization routine. Configuration
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syntax differs depending on the driver.
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</para>
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</section>
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<section><info><title>Sample DynDB Module</title></info>
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<para>
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For guidance in the implementation of DynDB modules, the directory
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<filename>bin/tests/system/dyndb/driver</filename>
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contains a basic DynDB module.
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The example sets up two zones, whose names are passed
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to the module as arguments in the <command>dyndb</command>
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statement:
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</para>
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<screen>
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dyndb sample "sample.so" { example.nil. arpa. };
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</screen>
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<para>
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In the above example, the module is configured to create a zone,
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"example.nil", which can answer queries and AXFR requests, and
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accept DDNS updates. At runtime, prior to any updates, the zone
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contains an SOA, NS, and a single A record at the apex:
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</para>
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<screen>
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example.nil. 86400 IN SOA example.nil. example.nil. (
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0 28800 7200 604800 86400
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)
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example.nil. 86400 IN NS example.nil.
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example.nil. 86400 IN A 127.0.0.1
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</screen>
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<para>
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When the zone is updated dynamically, the DynDB module determines
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whether the updated RR is an address (i.e., type A or AAAA); if
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so, it automatically updates the corresponding PTR record in a
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reverse zone. Note that updates are not stored permanently; all updates are
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lost when the server is restarted.
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</para>
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</section>
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</section>
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