Bv9ARM.ch04.html revision ac93437301f55ed69bf85883a497a75598c628f9
990d0e893f5b70e735cdf990af66e9ec6e91fa78Tinderbox User - Copyright (C) 2004-2009 Internet Systems Consortium, Inc. ("ISC")
75c0816e8295e180f4bc7f10db3d0d880383bc1cMark Andrews - Copyright (C) 2000-2003 Internet Software Consortium.
4a14ce5ba00ab7bc55c99ffdcf59c7a4ab902721Automatic Updater - Permission to use, copy, modify, and distribute this software for any
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein - purpose with or without fee is hereby granted, provided that the above
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein - copyright notice and this permission notice appear in all copies.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein - THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein - REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein - AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein - INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein - LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein - OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein - PERFORMANCE OF THIS SOFTWARE.
ea94d370123a5892f6c47a97f21d1b28d44bb168Tinderbox User<!-- $Id: Bv9ARM.ch04.html,v 1.94 2009/05/15 01:15:47 tbox Exp $ -->
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60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<link rel="start" href="Bv9ARM.html" title="BIND 9 Administrator Reference Manual">
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60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<link rel="prev" href="Bv9ARM.ch03.html" title="Chapter�3.�Name Server Configuration">
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<link rel="next" href="Bv9ARM.ch05.html" title="Chapter�5.�The BIND 9 Lightweight Resolver">
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60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<tr><th colspan="3" align="center">Chapter�4.�Advanced DNS Features</th></tr>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<a accesskey="p" href="Bv9ARM.ch03.html">Prev</a>�</td>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<td width="20%" align="right">�<a accesskey="n" href="Bv9ARM.ch05.html">Next</a>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<div class="titlepage"><div><div><h2 class="title">
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<a name="Bv9ARM.ch04"></a>Chapter�4.�Advanced DNS Features</h2></div></div></div>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<dt><span class="sect1"><a href="Bv9ARM.ch04.html#notify">Notify</a></span></dt>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<dt><span class="sect1"><a href="Bv9ARM.ch04.html#dynamic_update">Dynamic Update</a></span></dt>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<dd><dl><dt><span class="sect2"><a href="Bv9ARM.ch04.html#journal">The journal file</a></span></dt></dl></dd>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<dt><span class="sect1"><a href="Bv9ARM.ch04.html#incremental_zone_transfers">Incremental Zone Transfers (IXFR)</a></span></dt>
5fa6a064b8301e4f274bd132fd577def59e4fb4cTinderbox User<dt><span class="sect1"><a href="Bv9ARM.ch04.html#id2564066">Split DNS</a></span></dt>
5fa6a064b8301e4f274bd132fd577def59e4fb4cTinderbox User<dd><dl><dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2564084">Example split DNS setup</a></span></dt></dl></dd>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<dt><span class="sect1"><a href="Bv9ARM.ch04.html#tsig">TSIG</a></span></dt>
5fa6a064b8301e4f274bd132fd577def59e4fb4cTinderbox User<dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2571139">Generate Shared Keys for Each Pair of Hosts</a></span></dt>
5fa6a064b8301e4f274bd132fd577def59e4fb4cTinderbox User<dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2571212">Copying the Shared Secret to Both Machines</a></span></dt>
5fa6a064b8301e4f274bd132fd577def59e4fb4cTinderbox User<dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2571223">Informing the Servers of the Key's Existence</a></span></dt>
5fa6a064b8301e4f274bd132fd577def59e4fb4cTinderbox User<dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2571266">Instructing the Server to Use the Key</a></span></dt>
5fa6a064b8301e4f274bd132fd577def59e4fb4cTinderbox User<dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2571323">TSIG Key Based Access Control</a></span></dt>
5fa6a064b8301e4f274bd132fd577def59e4fb4cTinderbox User<dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2571440">Errors</a></span></dt>
5fa6a064b8301e4f274bd132fd577def59e4fb4cTinderbox User<dt><span class="sect1"><a href="Bv9ARM.ch04.html#id2571453">TKEY</a></span></dt>
5fa6a064b8301e4f274bd132fd577def59e4fb4cTinderbox User<dt><span class="sect1"><a href="Bv9ARM.ch04.html#id2571639">SIG(0)</a></span></dt>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<dt><span class="sect1"><a href="Bv9ARM.ch04.html#DNSSEC">DNSSEC</a></span></dt>
5fa6a064b8301e4f274bd132fd577def59e4fb4cTinderbox User<dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2571776">Generating Keys</a></span></dt>
5fa6a064b8301e4f274bd132fd577def59e4fb4cTinderbox User<dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2571854">Signing the Zone</a></span></dt>
5fa6a064b8301e4f274bd132fd577def59e4fb4cTinderbox User<dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2571936">Configuring Servers</a></span></dt>
6f64d4ab8e68f9b2333bcbfc755396d29a4a9d7cAutomatic Updater<dt><span class="sect1"><a href="Bv9ARM.ch04.html#id2572242">IPv6 Support in <acronym class="acronym">BIND</acronym> 9</a></span></dt>
60c29cf21affb5243753e22f9ff43347013ae8ebTinderbox User<dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2572304">Address Lookups Using AAAA Records</a></span></dt>
60c29cf21affb5243753e22f9ff43347013ae8ebTinderbox User<dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2572325">Address to Name Lookups Using Nibble Format</a></span></dt>
b68a2d272b958eb2c40cce59ee33e71c5f5f521bTinderbox User<div class="titlepage"><div><div><h2 class="title" style="clear: both">
b68a2d272b958eb2c40cce59ee33e71c5f5f521bTinderbox User<a name="notify"></a>Notify</h2></div></div></div>
b68a2d272b958eb2c40cce59ee33e71c5f5f521bTinderbox User <acronym class="acronym">DNS</acronym> NOTIFY is a mechanism that allows master
b68a2d272b958eb2c40cce59ee33e71c5f5f521bTinderbox User servers to notify their slave servers of changes to a zone's data. In
b68a2d272b958eb2c40cce59ee33e71c5f5f521bTinderbox User response to a <span><strong class="command">NOTIFY</strong></span> from a master server, the
b68a2d272b958eb2c40cce59ee33e71c5f5f521bTinderbox User slave will check to see that its version of the zone is the
6f64d4ab8e68f9b2333bcbfc755396d29a4a9d7cAutomatic Updater current version and, if not, initiate a zone transfer.
b68a2d272b958eb2c40cce59ee33e71c5f5f521bTinderbox User For more information about <acronym class="acronym">DNS</acronym>
b68a2d272b958eb2c40cce59ee33e71c5f5f521bTinderbox User <span><strong class="command">NOTIFY</strong></span>, see the description of the
bbbf2e27d3a981163dab139497d6b2dc85449db0Tinderbox User <span><strong class="command">notify</strong></span> option in <a href="Bv9ARM.ch06.html#boolean_options" title="Boolean Options">the section called “Boolean Options”</a> and
bbbf2e27d3a981163dab139497d6b2dc85449db0Tinderbox User the description of the zone option <span><strong class="command">also-notify</strong></span> in
bbbf2e27d3a981163dab139497d6b2dc85449db0Tinderbox User <a href="Bv9ARM.ch06.html#zone_transfers" title="Zone Transfers">the section called “Zone Transfers”</a>. The <span><strong class="command">NOTIFY</strong></span>
60c29cf21affb5243753e22f9ff43347013ae8ebTinderbox User protocol is specified in RFC 1996.
b68a2d272b958eb2c40cce59ee33e71c5f5f521bTinderbox User<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
b68a2d272b958eb2c40cce59ee33e71c5f5f521bTinderbox User As a slave zone can also be a master to other slaves, <span><strong class="command">named</strong></span>,
b68a2d272b958eb2c40cce59ee33e71c5f5f521bTinderbox User by default, sends <span><strong class="command">NOTIFY</strong></span> messages for every zone
b68a2d272b958eb2c40cce59ee33e71c5f5f521bTinderbox User it loads. Specifying <span><strong class="command">notify master-only;</strong></span> will
44d0f0256fbdce130a18655023c3b06bacacbd61Automatic Updater cause <span><strong class="command">named</strong></span> to only send <span><strong class="command">NOTIFY</strong></span> for master
bcf15a19ae0efa72a22cdfb50666a3c6ce39eb9fTinderbox User zones that it loads.
bcf15a19ae0efa72a22cdfb50666a3c6ce39eb9fTinderbox User<div class="titlepage"><div><div><h2 class="title" style="clear: both">
5fa6a064b8301e4f274bd132fd577def59e4fb4cTinderbox User<a name="dynamic_update"></a>Dynamic Update</h2></div></div></div>
5fa6a064b8301e4f274bd132fd577def59e4fb4cTinderbox User Dynamic Update is a method for adding, replacing or deleting
5fa6a064b8301e4f274bd132fd577def59e4fb4cTinderbox User records in a master server by sending it a special form of DNS
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein messages. The format and meaning of these messages is specified
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein in RFC 2136.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Dynamic update is enabled by including an
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <span><strong class="command">allow-update</strong></span> or <span><strong class="command">update-policy</strong></span>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein clause in the <span><strong class="command">zone</strong></span> statement. The
71c66a876ecca77923638d3f94cc0783152b2f03Mark Andrews <span><strong class="command">tkey-gssapi-credential</strong></span> and
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <span><strong class="command">tkey-domain</strong></span> clauses in the
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <span><strong class="command">options</strong></span> statement enable the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein server to negotiate keys that can be matched against those
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein in <span><strong class="command">update-policy</strong></span> or
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <span><strong class="command">allow-update</strong></span>.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Updating of secure zones (zones using DNSSEC) follows RFC
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein 3007: RRSIG, NSEC and NSEC3 records affected by updates are
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein automatically regenerated by the server using an online
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein zone key. Update authorization is based on transaction
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein signatures and an explicit server policy.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews<div class="titlepage"><div><div><h3 class="title">
58d9e9169e7ab4355a0b0bfc13bc616bc5247dfeAutomatic Updater<a name="journal"></a>The journal file</h3></div></div></div>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews All changes made to a zone using dynamic update are stored
58d9e9169e7ab4355a0b0bfc13bc616bc5247dfeAutomatic Updater in the zone's journal file. This file is automatically created
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews by the server when the first dynamic update takes place.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews The name of the journal file is formed by appending the extension
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <code class="filename">.jnl</code> to the name of the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein corresponding zone
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein file unless specifically overridden. The journal file is in a
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein binary format and should not be edited manually.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein The server will also occasionally write ("dump")
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein the complete contents of the updated zone to its zone file.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein This is not done immediately after
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein each dynamic update, because that would be too slow when a large
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein zone is updated frequently. Instead, the dump is delayed by
acb72d5e2c83b597332e3eb0c7d59e1142f1adfdMark Andrews up to 15 minutes, allowing additional updates to take place.
852ccdd42a71550c974111b49415204ffeca6573Automatic Updater When a server is restarted after a shutdown or crash, it will replay
852ccdd42a71550c974111b49415204ffeca6573Automatic Updater the journal file to incorporate into the zone any updates that
3cddb2c552ee6582e8db0849c28747f6b6ca57feAutomatic Updater place after the last zone dump.
3cddb2c552ee6582e8db0849c28747f6b6ca57feAutomatic Updater Changes that result from incoming incremental zone transfers are
852ccdd42a71550c974111b49415204ffeca6573Automatic Updater journalled in a similar way.
66f25f2ceeb589e67efe7af2413baaa3426b0042Automatic Updater The zone files of dynamic zones cannot normally be edited by
66f25f2ceeb589e67efe7af2413baaa3426b0042Automatic Updater hand because they are not guaranteed to contain the most recent
66f25f2ceeb589e67efe7af2413baaa3426b0042Automatic Updater dynamic changes — those are only in the journal file.
66f25f2ceeb589e67efe7af2413baaa3426b0042Automatic Updater The only way to ensure that the zone file of a dynamic zone
66f25f2ceeb589e67efe7af2413baaa3426b0042Automatic Updater is up to date is to run <span><strong class="command">rndc stop</strong></span>.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein If you have to make changes to a dynamic zone
38417cbfb1a328c20b5b723b8584a02c57f88897Automatic Updater manually, the following procedure will work: Disable dynamic updates
38417cbfb1a328c20b5b723b8584a02c57f88897Automatic Updater to the zone using
38417cbfb1a328c20b5b723b8584a02c57f88897Automatic Updater <span><strong class="command">rndc freeze <em class="replaceable"><code>zone</code></em></strong></span>.
38417cbfb1a328c20b5b723b8584a02c57f88897Automatic Updater This will also remove the zone's <code class="filename">.jnl</code> file
38417cbfb1a328c20b5b723b8584a02c57f88897Automatic Updater and update the master file. Edit the zone file. Run
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <span><strong class="command">rndc thaw <em class="replaceable"><code>zone</code></em></strong></span>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein to reload the changed zone and re-enable dynamic updates.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<div class="titlepage"><div><div><h2 class="title" style="clear: both">
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<a name="incremental_zone_transfers"></a>Incremental Zone Transfers (IXFR)</h2></div></div></div>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein The incremental zone transfer (IXFR) protocol is a way for
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein slave servers to transfer only changed data, instead of having to
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein transfer the entire zone. The IXFR protocol is specified in RFC
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein 1995. See <a href="Bv9ARM.ch09.html#proposed_standards">Proposed Standards</a>.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein When acting as a master, <acronym class="acronym">BIND</acronym> 9
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein supports IXFR for those zones
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein where the necessary change history information is available. These
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein include master zones maintained by dynamic update and slave zones
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein whose data was obtained by IXFR. For manually maintained master
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein zones, and for slave zones obtained by performing a full zone
3a5fe5abf08f16b8d31ab8ee9a788063110ef000Automatic Updater transfer (AXFR), IXFR is supported only if the option
3a5fe5abf08f16b8d31ab8ee9a788063110ef000Automatic Updater <span><strong class="command">ixfr-from-differences</strong></span> is set
3a5fe5abf08f16b8d31ab8ee9a788063110ef000Automatic Updater to <strong class="userinput"><code>yes</code></strong>.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein When acting as a slave, <acronym class="acronym">BIND</acronym> 9 will
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein attempt to use IXFR unless
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein it is explicitly disabled. For more information about disabling
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein IXFR, see the description of the <span><strong class="command">request-ixfr</strong></span> clause
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein of the <span><strong class="command">server</strong></span> statement.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<div class="titlepage"><div><div><h2 class="title" style="clear: both">
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<a name="id2564066"></a>Split DNS</h2></div></div></div>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Setting up different views, or visibility, of the DNS space to
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein internal and external resolvers is usually referred to as a
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <span class="emphasis"><em>Split DNS</em></span> setup. There are several
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein reasons an organization would want to set up its DNS this way.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein One common reason for setting up a DNS system this way is
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein to hide "internal" DNS information from "external" clients on the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Internet. There is some debate as to whether or not this is actually
794b79e6bbc3f5db1ea6ae154d739b9f1ef1a375Tinderbox User Internal DNS information leaks out in many ways (via email headers,
794b79e6bbc3f5db1ea6ae154d739b9f1ef1a375Tinderbox User for example) and most savvy "attackers" can find the information
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein they need using other means.
794b79e6bbc3f5db1ea6ae154d739b9f1ef1a375Tinderbox User However, since listing addresses of internal servers that
794b79e6bbc3f5db1ea6ae154d739b9f1ef1a375Tinderbox User external clients cannot possibly reach can result in
794b79e6bbc3f5db1ea6ae154d739b9f1ef1a375Tinderbox User connection delays and other annoyances, an organization may
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews choose to use a Split DNS to present a consistent view of itself
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein to the outside world.
794b79e6bbc3f5db1ea6ae154d739b9f1ef1a375Tinderbox User Another common reason for setting up a Split DNS system is
794b79e6bbc3f5db1ea6ae154d739b9f1ef1a375Tinderbox User to allow internal networks that are behind filters or in RFC 1918
794b79e6bbc3f5db1ea6ae154d739b9f1ef1a375Tinderbox User space (reserved IP space, as documented in RFC 1918) to resolve DNS
794b79e6bbc3f5db1ea6ae154d739b9f1ef1a375Tinderbox User on the Internet. Split DNS can also be used to allow mail from outside
794b79e6bbc3f5db1ea6ae154d739b9f1ef1a375Tinderbox User back in to the internal network.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<div class="titlepage"><div><div><h3 class="title">
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<a name="id2564084"></a>Example split DNS setup</h3></div></div></div>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Let's say a company named <span class="emphasis"><em>Example, Inc.</em></span>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein has several corporate sites that have an internal network with
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Internet Protocol (IP) space and an external demilitarized zone (DMZ),
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein or "outside" section of a network, that is available to the public.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <span class="emphasis"><em>Example, Inc.</em></span> wants its internal clients
71c66a876ecca77923638d3f94cc0783152b2f03Mark Andrews to be able to resolve external hostnames and to exchange mail with
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein people on the outside. The company also wants its internal resolvers
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein to have access to certain internal-only zones that are not available
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein at all outside of the internal network.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein In order to accomplish this, the company will set up two sets
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein of name servers. One set will be on the inside network (in the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein IP space) and the other set will be on bastion hosts, which are
71c66a876ecca77923638d3f94cc0783152b2f03Mark Andrews hosts that can talk to both sides of its network, in the DMZ.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein The internal servers will be configured to forward all queries,
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein except queries for <code class="filename">site1.internal</code>, <code class="filename">site2.internal</code>, <code class="filename">site1.example.com</code>,
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein and <code class="filename">site2.example.com</code>, to the servers
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein DMZ. These internal servers will have complete sets of information
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein for <code class="filename">site1.example.com</code>, <code class="filename">site2.example.com</code>, <code class="filename">site1.internal</code>,
5fa6a064b8301e4f274bd132fd577def59e4fb4cTinderbox User and <code class="filename">site2.internal</code>.
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews To protect the <code class="filename">site1.internal</code> and <code class="filename">site2.internal</code> domains,
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews the internal name servers must be configured to disallow all queries
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews to these domains from any external hosts, including the bastion
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein The external servers, which are on the bastion hosts, will
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein be configured to serve the "public" version of the <code class="filename">site1</code> and <code class="filename">site2.example.com</code> zones.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein This could include things such as the host records for public servers
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein (<code class="filename">www.example.com</code> and <code class="filename">ftp.example.com</code>),
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein and mail exchange (MX) records (<code class="filename">a.mx.example.com</code> and <code class="filename">b.mx.example.com</code>).
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews In addition, the public <code class="filename">site1</code> and <code class="filename">site2.example.com</code> zones
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews should have special MX records that contain wildcard (`*') records
a1b05dea35aa30b152a47115e18bbe679d3fcf19Mark Andrews pointing to the bastion hosts. This is needed because external mail
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews servers do not have any other way of looking up how to deliver mail
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein to those internal hosts. With the wildcard records, the mail will
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein be delivered to the bastion host, which can then forward it on to
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein internal hosts.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Here's an example of a wildcard MX record:
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<pre class="programlisting">* IN MX 10 external1.example.com.</pre>
bea931e17b7567f09107f93ab7e25c7f00abeb9cMark Andrews Now that they accept mail on behalf of anything in the internal
5fa6a064b8301e4f274bd132fd577def59e4fb4cTinderbox User network, the bastion hosts will need to know how to deliver mail
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein to internal hosts. In order for this to work properly, the resolvers
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein the bastion hosts will need to be configured to point to the internal
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein name servers for DNS resolution.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Queries for internal hostnames will be answered by the internal
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein servers, and queries for external hostnames will be forwarded back
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein out to the DNS servers on the bastion hosts.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein In order for all this to work properly, internal clients will
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein need to be configured to query <span class="emphasis"><em>only</em></span> the internal
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein name servers for DNS queries. This could also be enforced via
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein filtering on the network.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein If everything has been set properly, <span class="emphasis"><em>Example, Inc.</em></span>'s
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein internal clients will now be able to:
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Look up any hostnames in the <code class="literal">site1</code>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <code class="literal">site2.example.com</code> zones.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Look up any hostnames in the <code class="literal">site1.internal</code> and
2cc6eb92f9443695bc32fa6eed372d983d261a35Automatic Updater <code class="literal">site2.internal</code> domains.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<li>Exchange mail with both internal and external people.</li>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Hosts on the Internet will be able to:
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Look up any hostnames in the <code class="literal">site1</code>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <code class="literal">site2.example.com</code> zones.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Exchange mail with anyone in the <code class="literal">site1</code> and
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <code class="literal">site2.example.com</code> zones.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Here is an example configuration for the setup we just
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein described above. Note that this is only configuration information;
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein for information on how to configure your zone files, see <a href="Bv9ARM.ch03.html#sample_configuration" title="Sample Configurations">the section called “Sample Configurations”</a>.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Internal DNS server config:
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinacl internals { 172.16.72.0/24; 192.168.1.0/24; };
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinacl externals { <code class="varname">bastion-ips-go-here</code>; };
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein forward only;
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein // forward to external servers
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein forwarders {
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <code class="varname">bastion-ips-go-here</code>;
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein // sample allow-transfer (no one)
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein allow-transfer { none; };
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein // restrict query access
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein allow-query { internals; externals; };
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein // restrict recursion
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein allow-recursion { internals; };
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein// sample master zone
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein type master;
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein // do normal iterative resolution (do not forward)
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein forwarders { };
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein allow-query { internals; externals; };
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein allow-transfer { internals; };
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein// sample slave zone
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein masters { 172.16.72.3; };
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein forwarders { };
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein allow-query { internals; externals; };
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein allow-transfer { internals; };
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein type master;
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein forwarders { };
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein allow-query { internals; };
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein allow-transfer { internals; }
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein masters { 172.16.72.3; };
47012ae6dbf18a2503d7b33c1c9583dc38625cb7Mark Andrews forwarders { };
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein allow-query { internals };
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein allow-transfer { internals; }
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein External (bastion host) DNS server config:
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinacl internals { 172.16.72.0/24; 192.168.1.0/24; };
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luceacl externals { bastion-ips-go-here; };
ac93437301f55ed69bf85883a497a75598c628f9Automatic Updater // sample allow-transfer (no one)
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews allow-transfer { none; };
c71787bd6356c92e9c7d0a174cd63ab17fcf34c6Eric Luce // default query access
ac93437301f55ed69bf85883a497a75598c628f9Automatic Updater allow-query { any; };
ac93437301f55ed69bf85883a497a75598c628f9Automatic Updater // restrict cache access
ac93437301f55ed69bf85883a497a75598c628f9Automatic Updater allow-query-cache { internals; externals; };
ac93437301f55ed69bf85883a497a75598c628f9Automatic Updater // restrict recursion
ac93437301f55ed69bf85883a497a75598c628f9Automatic Updater allow-recursion { internals; externals; };
c71787bd6356c92e9c7d0a174cd63ab17fcf34c6Eric Luce// sample slave zone
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce allow-transfer { internals; externals; };
c71787bd6356c92e9c7d0a174cd63ab17fcf34c6Eric Luce masters { another_bastion_host_maybe; };
ac93437301f55ed69bf85883a497a75598c628f9Automatic Updater allow-transfer { internals; externals; }
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce In the <code class="filename">resolv.conf</code> (or equivalent) on
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce the bastion host(s):
c71787bd6356c92e9c7d0a174cd63ab17fcf34c6Eric Lucenameserver 172.16.72.2
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucenameserver 172.16.72.3
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Lucenameserver 172.16.72.4
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce<div class="titlepage"><div><div><h2 class="title" style="clear: both">
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce This is a short guide to setting up Transaction SIGnatures
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce (TSIG) based transaction security in <acronym class="acronym">BIND</acronym>. It describes changes
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce to the configuration file as well as what changes are required for
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce different features, including the process of creating transaction
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce keys and using transaction signatures with <acronym class="acronym">BIND</acronym>.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <acronym class="acronym">BIND</acronym> primarily supports TSIG for server
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein to server communication.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein This includes zone transfer, notify, and recursive query messages.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Resolvers based on newer versions of <acronym class="acronym">BIND</acronym> 8 have limited support
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce TSIG can also be useful for dynamic update. A primary
c71787bd6356c92e9c7d0a174cd63ab17fcf34c6Eric Luce server for a dynamic zone should control access to the dynamic
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce update service, but IP-based access control is insufficient.
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce The cryptographic access control provided by TSIG
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce is far superior. The <span><strong class="command">nsupdate</strong></span>
ac93437301f55ed69bf85883a497a75598c628f9Automatic Updater program supports TSIG via the <code class="option">-k</code> and
ac93437301f55ed69bf85883a497a75598c628f9Automatic Updater <code class="option">-y</code> command line options or inline by use
ac93437301f55ed69bf85883a497a75598c628f9Automatic Updater of the <span><strong class="command">key</strong></span>.
ac93437301f55ed69bf85883a497a75598c628f9Automatic Updater<div class="titlepage"><div><div><h3 class="title">
ac93437301f55ed69bf85883a497a75598c628f9Automatic Updater<a name="id2571139"></a>Generate Shared Keys for Each Pair of Hosts</h3></div></div></div>
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce A shared secret is generated to be shared between <span class="emphasis"><em>host1</em></span> and <span class="emphasis"><em>host2</em></span>.
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce An arbitrary key name is chosen: "host1-host2.". The key name must
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce be the same on both hosts.
ac93437301f55ed69bf85883a497a75598c628f9Automatic Updater<div class="titlepage"><div><div><h4 class="title">
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce<a name="id2571156"></a>Automatic Generation</h4></div></div></div>
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce The following command will generate a 128-bit (16 byte) HMAC-MD5
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce key as described above. Longer keys are better, but shorter keys
c71787bd6356c92e9c7d0a174cd63ab17fcf34c6Eric Luce are easier to read. Note that the maximum key length is 512 bits;
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce keys longer than that will be digested with MD5 to produce a
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce 128-bit key.
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce <strong class="userinput"><code>dnssec-keygen -a hmac-md5 -b 128 -n HOST host1-host2.</code></strong>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein The key is in the file <code class="filename">Khost1-host2.+157+00000.private</code>.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Nothing directly uses this file, but the base-64 encoded string
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein can be extracted from the file and used as a shared secret:
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<pre class="programlisting">Key: La/E5CjG9O+os1jq0a2jdA==</pre>
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce The string "<code class="literal">La/E5CjG9O+os1jq0a2jdA==</code>" can
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce be used as the shared secret.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<div class="titlepage"><div><div><h4 class="title">
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<a name="id2571194"></a>Manual Generation</h4></div></div></div>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein The shared secret is simply a random sequence of bits, encoded
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein in base-64. Most ASCII strings are valid base-64 strings (assuming
71c66a876ecca77923638d3f94cc0783152b2f03Mark Andrews the length is a multiple of 4 and only valid characters are used),
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein so the shared secret can be manually generated.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Also, a known string can be run through <span><strong class="command">mmencode</strong></span> or
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein a similar program to generate base-64 encoded data.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<div class="titlepage"><div><div><h3 class="title">
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<a name="id2571212"></a>Copying the Shared Secret to Both Machines</h3></div></div></div>
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews This is beyond the scope of DNS. A secure transport mechanism
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews should be used. This could be secure FTP, ssh, telephone, etc.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<div class="titlepage"><div><div><h3 class="title">
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews<a name="id2571223"></a>Informing the Servers of the Key's Existence</h3></div></div></div>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Imagine <span class="emphasis"><em>host1</em></span> and <span class="emphasis"><em>host 2</em></span>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein both servers. The following is added to each server's <code class="filename">named.conf</code> file:
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeinkey host1-host2. {
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein algorithm hmac-md5;
5fa6a064b8301e4f274bd132fd577def59e4fb4cTinderbox User The algorithm, <code class="literal">hmac-md5</code>, is the only one supported by <acronym class="acronym">BIND</acronym>.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein The secret is the one generated above. Since this is a secret, it
8ec3c085233cedb22b05da36e2773c8f357a7e45Automatic Updater is recommended that either <code class="filename">named.conf</code> be non-world
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein readable, or the key directive be added to a non-world readable
8ec3c085233cedb22b05da36e2773c8f357a7e45Automatic Updater file that is included by
8ec3c085233cedb22b05da36e2773c8f357a7e45Automatic Updater At this point, the key is recognized. This means that if the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein server receives a message signed by this key, it can verify the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein signature. If the signature is successfully verified, the
8ec3c085233cedb22b05da36e2773c8f357a7e45Automatic Updater response is signed by the same key.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<div class="titlepage"><div><div><h3 class="title">
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<a name="id2571266"></a>Instructing the Server to Use the Key</h3></div></div></div>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Since keys are shared between two hosts only, the server must
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein be told when keys are to be used. The following is added to the <code class="filename">named.conf</code> file
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein for <span class="emphasis"><em>host1</em></span>, if the IP address of <span class="emphasis"><em>host2</em></span> is
5fa6a064b8301e4f274bd132fd577def59e4fb4cTinderbox Userserver 10.1.2.3 {
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein keys { host1-host2. ;};
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Multiple keys may be present, but only the first is used.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein This directive does not contain any secrets, so it may be in a
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein world-readable
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein If <span class="emphasis"><em>host1</em></span> sends a message that is a request
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein to that address, the message will be signed with the specified key. <span class="emphasis"><em>host1</em></span> will
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein expect any responses to signed messages to be signed with the same
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein A similar statement must be present in <span class="emphasis"><em>host2</em></span>'s
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein configuration file (with <span class="emphasis"><em>host1</em></span>'s address) for <span class="emphasis"><em>host2</em></span> to
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein sign request messages to <span class="emphasis"><em>host1</em></span>.
5fa6a064b8301e4f274bd132fd577def59e4fb4cTinderbox User<div class="titlepage"><div><div><h3 class="title">
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<a name="id2571323"></a>TSIG Key Based Access Control</h3></div></div></div>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <acronym class="acronym">BIND</acronym> allows IP addresses and ranges
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein to be specified in ACL
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein definitions and
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <span><strong class="command">allow-{ query | transfer | update }</strong></span>
8ec3c085233cedb22b05da36e2773c8f357a7e45Automatic Updater This has been extended to allow TSIG keys also. The above key would
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce be denoted <span><strong class="command">key host1-host2.</strong></span>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein An example of an <span><strong class="command">allow-update</strong></span> directive would be:
8ec3c085233cedb22b05da36e2773c8f357a7e45Automatic Updaterallow-update { key host1-host2. ;};
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein This allows dynamic updates to succeed only if the request
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein was signed by a key named "<span><strong class="command">host1-host2.</strong></span>".
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein You may want to read about the more powerful
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <span><strong class="command">update-policy</strong></span> statement in
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <a href="Bv9ARM.ch06.html#dynamic_update_policies" title="Dynamic Update Policies">the section called “Dynamic Update Policies”</a>.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<div class="titlepage"><div><div><h3 class="title">
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<a name="id2571440"></a>Errors</h3></div></div></div>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein The processing of TSIG signed messages can result in
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein several errors. If a signed message is sent to a non-TSIG aware
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein server, a FORMERR (format error) will be returned, since the server will not
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein understand the record. This is a result of misconfiguration,
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein since the server must be explicitly configured to send a TSIG
f293a69bcd1c1dd7bdac8f4102fc2398b9e475c8Eric Luce signed message to a specific server.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein If a TSIG aware server receives a message signed by an
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein unknown key, the response will be unsigned with the TSIG
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein extended error code set to BADKEY. If a TSIG aware server
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein receives a message with a signature that does not validate, the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein response will be unsigned with the TSIG extended error code set
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein to BADSIG. If a TSIG aware server receives a message with a time
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein outside of the allowed range, the response will be signed with
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein the TSIG extended error code set to BADTIME, and the time values
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein will be adjusted so that the response can be successfully
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein verified. In any of these cases, the message's rcode (response code) is set to
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein NOTAUTH (not authenticated).
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<div class="titlepage"><div><div><h2 class="title" style="clear: both">
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<a name="id2571453"></a>TKEY</h2></div></div></div>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<p><span><strong class="command">TKEY</strong></span>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein is a mechanism for automatically generating a shared secret
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein between two hosts. There are several "modes" of
5fa6a064b8301e4f274bd132fd577def59e4fb4cTinderbox User <span><strong class="command">TKEY</strong></span> that specify how the key is generated
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein or assigned. <acronym class="acronym">BIND</acronym> 9 implements only one of
71c66a876ecca77923638d3f94cc0783152b2f03Mark Andrews these modes, the Diffie-Hellman key exchange. Both hosts are
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein required to have a Diffie-Hellman KEY record (although this
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein record is not required to be present in a zone). The
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <span><strong class="command">TKEY</strong></span> process must use signed messages,
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein signed either by TSIG or SIG(0). The result of
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <span><strong class="command">TKEY</strong></span> is a shared secret that can be used to
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein sign messages with TSIG. <span><strong class="command">TKEY</strong></span> can also be
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein used to delete shared secrets that it had previously
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein The <span><strong class="command">TKEY</strong></span> process is initiated by a
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein or server by sending a signed <span><strong class="command">TKEY</strong></span>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein (including any appropriate KEYs) to a TKEY-aware server. The
acb72d5e2c83b597332e3eb0c7d59e1142f1adfdMark Andrews server response, if it indicates success, will contain a
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <span><strong class="command">TKEY</strong></span> record and any appropriate keys.
3cddb2c552ee6582e8db0849c28747f6b6ca57feAutomatic Updater this exchange, both participants have enough information to
3cddb2c552ee6582e8db0849c28747f6b6ca57feAutomatic Updater determine the shared secret; the exact process depends on the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <span><strong class="command">TKEY</strong></span> mode. When using the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Diffie-Hellman
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <span><strong class="command">TKEY</strong></span> mode, Diffie-Hellman keys are
5fa6a064b8301e4f274bd132fd577def59e4fb4cTinderbox User and the shared secret is derived by both participants.
47012ae6dbf18a2503d7b33c1c9583dc38625cb7Mark Andrews<div class="titlepage"><div><div><h2 class="title" style="clear: both">
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<a name="id2571639"></a>SIG(0)</h2></div></div></div>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <acronym class="acronym">BIND</acronym> 9 partially supports DNSSEC SIG(0)
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein transaction signatures as specified in RFC 2535 and RFC 2931.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein uses public/private keys to authenticate messages. Access control
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein is performed in the same manner as TSIG keys; privileges can be
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein granted or denied based on the key name.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein When a SIG(0) signed message is received, it will only be
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein verified if the key is known and trusted by the server; the server
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein will not attempt to locate and/or validate the key.
47012ae6dbf18a2503d7b33c1c9583dc38625cb7Mark Andrews SIG(0) signing of multiple-message TCP streams is not
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein The only tool shipped with <acronym class="acronym">BIND</acronym> 9 that
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein generates SIG(0) signed messages is <span><strong class="command">nsupdate</strong></span>.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<div class="titlepage"><div><div><h2 class="title" style="clear: both">
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<a name="DNSSEC"></a>DNSSEC</h2></div></div></div>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Cryptographic authentication of DNS information is possible
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein through the DNS Security (<span class="emphasis"><em>DNSSEC-bis</em></span>) extensions,
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein defined in RFC 4033, RFC 4034, and RFC 4035.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein This section describes the creation and use of DNSSEC signed zones.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein In order to set up a DNSSEC secure zone, there are a series
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein of steps which must be followed. <acronym class="acronym">BIND</acronym>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein with several tools
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein that are used in this process, which are explained in more detail
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein below. In all cases, the <code class="option">-h</code> option prints a
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein full list of parameters. Note that the DNSSEC tools require the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein keyset files to be in the working directory or the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein directory specified by the <code class="option">-d</code> option, and
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein that the tools shipped with BIND 9.2.x and earlier are not compatible
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein with the current ones.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein There must also be communication with the administrators of
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein the parent and/or child zone to transmit keys. A zone's security
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein status must be indicated by the parent zone for a DNSSEC capable
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein resolver to trust its data. This is done through the presence
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein or absence of a <code class="literal">DS</code> record at the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein For other servers to trust data in this zone, they must
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein either be statically configured with this zone's zone key or the
5fa6a064b8301e4f274bd132fd577def59e4fb4cTinderbox User zone key of another zone above this one in the DNS tree.
a1ad6695ed6f988406cf155aa26376f84f73bcb9Automatic Updater<div class="titlepage"><div><div><h3 class="title">
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<a name="id2571776"></a>Generating Keys</h3></div></div></div>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein The <span><strong class="command">dnssec-keygen</strong></span> program is used to
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein generate keys.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein A secure zone must contain one or more zone keys. The
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein zone keys will sign all other records in the zone, as well as
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein the zone keys of any secure delegated zones. Zone keys must
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein have the same name as the zone, a name type of
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <span><strong class="command">ZONE</strong></span>, and must be usable for
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein authentication.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein It is recommended that zone keys use a cryptographic algorithm
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein designated as "mandatory to implement" by the IETF; currently
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein the only one is RSASHA1.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein The following command will generate a 768-bit RSASHA1 key for
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein the <code class="filename">child.example</code> zone:
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <strong class="userinput"><code>dnssec-keygen -a RSASHA1 -b 768 -n ZONE child.example.</code></strong>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Two output files will be produced:
bea931e17b7567f09107f93ab7e25c7f00abeb9cMark Andrews <code class="filename">Kchild.example.+005+12345.key</code> and
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews <code class="filename">Kchild.example.+005+12345.private</code>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein 12345 is an example of a key tag). The key filenames contain
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein the key name (<code class="filename">child.example.</code>),
71c66a876ecca77923638d3f94cc0783152b2f03Mark Andrews algorithm (3
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein is DSA, 1 is RSAMD5, 5 is RSASHA1, etc.), and the key tag (12345 in
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein The private key (in the <code class="filename">.private</code>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein used to generate signatures, and the public key (in the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <code class="filename">.key</code> file) is used for signature
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews verification.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein To generate another key with the same properties (but with
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein a different key tag), repeat the above command.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein The <span><strong class="command">dnssec-keyfromlabel</strong></span> program is used
47012ae6dbf18a2503d7b33c1c9583dc38625cb7Mark Andrews to get a key pair from a crypto hardware and build the key
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein files. Its usage is similar to <span><strong class="command">dnssec-keygen</strong></span>.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein The public keys should be inserted into the zone file by
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein including the <code class="filename">.key</code> files using
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <span><strong class="command">$INCLUDE</strong></span> statements.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<div class="titlepage"><div><div><h3 class="title">
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<a name="id2571854"></a>Signing the Zone</h3></div></div></div>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein The <span><strong class="command">dnssec-signzone</strong></span> program is used
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein to sign a zone.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Any <code class="filename">keyset</code> files corresponding to
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein secure subzones should be present. The zone signer will
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein generate <code class="literal">NSEC</code>, <code class="literal">NSEC3</code>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein and <code class="literal">RRSIG</code> records for the zone, as
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein well as <code class="literal">DS</code> for the child zones if
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <code class="literal">'-g'</code> is specified. If <code class="literal">'-g'</code>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein is not specified, then DS RRsets for the secure child
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein zones need to be added manually.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein The following command signs the zone, assuming it is in a
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein file called <code class="filename">zone.child.example</code>. By
b05bdb520d83f7ecaad708fe305268c3420be01dMark Andrews default, all zone keys which have an available private key are
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein used to generate signatures.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <strong class="userinput"><code>dnssec-signzone -o child.example zone.child.example</code></strong>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein One output file is produced:
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <code class="filename">zone.child.example.signed</code>. This
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein should be referenced by <code class="filename">named.conf</code>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein input file for the zone.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<p><span><strong class="command">dnssec-signzone</strong></span>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein will also produce a keyset and dsset files and optionally a
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein dlvset file. These are used to provide the parent zone
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein administrators with the <code class="literal">DNSKEYs</code> (or their
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein corresponding <code class="literal">DS</code> records) that are the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein secure entry point to the zone.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<div class="titlepage"><div><div><h3 class="title">
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein<a name="id2571936"></a>Configuring Servers</h3></div></div></div>
28b3569d6248168e6c00caab951521cc8141a49dAutomatic Updater To enable <span><strong class="command">named</strong></span> to respond appropriately
28b3569d6248168e6c00caab951521cc8141a49dAutomatic Updater to DNS requests from DNSSEC aware clients,
28b3569d6248168e6c00caab951521cc8141a49dAutomatic Updater <span><strong class="command">dnssec-enable</strong></span> must be set to yes.
28b3569d6248168e6c00caab951521cc8141a49dAutomatic Updater (This is the default setting.)
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein To enable <span><strong class="command">named</strong></span> to validate answers from
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein other servers, the <span><strong class="command">dnssec-enable</strong></span> and
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <span><strong class="command">dnssec-validation</strong></span> options must both be
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein set to yes (the default setting in <acronym class="acronym">BIND</acronym> 9.5
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein and later), and at least one trust anchor must be configured
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein with a <span><strong class="command">trusted-keys</strong></span> statement in
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <span><strong class="command">trusted-keys</strong></span> are copies of DNSKEY RRs
38417cbfb1a328c20b5b723b8584a02c57f88897Automatic Updater for zones that are used to form the first link in the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein cryptographic chain of trust. All keys listed in
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein <span><strong class="command">trusted-keys</strong></span> (and corresponding zones)
38417cbfb1a328c20b5b723b8584a02c57f88897Automatic Updater are deemed to exist and only the listed keys will be used
38417cbfb1a328c20b5b723b8584a02c57f88897Automatic Updater to validated the DNSKEY RRset that they are from.
38417cbfb1a328c20b5b723b8584a02c57f88897Automatic Updater <span><strong class="command">trusted-keys</strong></span> are described in more detail
38417cbfb1a328c20b5b723b8584a02c57f88897Automatic Updater later in this document.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein Unlike <acronym class="acronym">BIND</acronym> 8, <acronym class="acronym">BIND</acronym>
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein 9 does not verify signatures on load, so zone keys for
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein authoritative zones do not need to be specified in the
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein configuration file.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein After DNSSEC gets established, a typical DNSSEC configuration
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein will look something like the following. It has a one or
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein more public keys for the root. This allows answers from
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein outside the organization to be validated. It will also
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein have several keys for parts of the namespace the organization
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein controls. These are here to ensure that <span><strong class="command">named</strong></span> is immune
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein to compromises in the DNSSEC components of the security
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein of parent zones.
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austeintrusted-keys {
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein /* Root Key */
5a4557e8de2951a2796676b5ec4b6a90caa5be14Mark Andrews"." 257 3 3 "BNY4wrWM1nCfJ+CXd0rVXyYmobt7sEEfK3clRbGaTwS
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein 66gKodQj+MiA21AfUVe7u99WzTLzY3qlxDhxYQQ20FQ
5fa6a064b8301e4f274bd132fd577def59e4fb4cTinderbox User dgxbcDTClU0CRBdiieyLMNzXG3";
6101b9f0d904a708e900a74abc16d1e0eda67264Mark Andrews/* Key for our organization's forward zone */
b05bdb520d83f7ecaad708fe305268c3420be01dMark Andrewsexample.com. 257 3 5 "AwEAAaxPMcR2x0HbQV4WeZB6oEDX+r0QM6
6101b9f0d904a708e900a74abc16d1e0eda67264Mark Andrews 5KbhTjrW1ZaARmPhEZZe3Y9ifgEuq7vZ/z
cbf7f1435f332b31f51a98611ccbfcd07c42c032Automatic Updater GZUdEGNWy+JZzus0lUptwgjGwhUS1558Hb
60e5e10f8d2e2b0c41e8abad38cacd867caa6ab2Rob Austein 4JKUbbOTcM8pwXlj0EiX3oDFVmjHO444gL
6101b9f0d904a708e900a74abc16d1e0eda67264Mark Andrews g4ywzO9WglMk7jbfW33gUKvirTHr25GL7S
ebabe300b615154d08f5577822cfd8726d2643c8Automatic Updater TQUzBb5Usxt8lgnyTUHs1t3JwCY5hKZ6Cq
ebabe300b615154d08f5577822cfd8726d2643c8Automatic Updater F4qJCyduieHukuY3H4XMAcR+xia2nIUPvm
ebabe300b615154d08f5577822cfd8726d2643c8Automatic Updater/* Key for our reverse zone. */
ebabe300b615154d08f5577822cfd8726d2643c8Automatic Updater2.0.192.IN-ADDRPA.NET. 257 3 5 "AQOnS4xn/IgOUpBPJ3bogzwc
ebabe300b615154d08f5577822cfd8726d2643c8Automatic Updater xOdNax071L18QqZnQQQAVVr+i
ebabe300b615154d08f5577822cfd8726d2643c8Automatic Updater LhGTnNGp3HoWQLUIzKrJVZ3zg
ebabe300b615154d08f5577822cfd8726d2643c8Automatic Updater gy3WwNT6kZo6c0tszYqbtvchm
2895f101b5585a19015ac2c2c1e1812ac467fa12Automatic Updater siaOdS0yOI6BgPsw+YZdzlYMa
ebabe300b615154d08f5577822cfd8726d2643c8Automatic Updater IJGf4M4dyoKIhzdZyQ2bYQrjy
ebabe300b615154d08f5577822cfd8726d2643c8Automatic Updater Q4LB0lC7aOnsMyYKHHYeRvPxj
ebabe300b615154d08f5577822cfd8726d2643c8Automatic Updater IQXmdqgOJGq+vsevG06zW+1xg
6101b9f0d904a708e900a74abc16d1e0eda67264Mark Andrews 59VvjSPsZJHeDCUyWYrvPZesZ
47012ae6dbf18a2503d7b33c1c9583dc38625cb7Mark Andrews DIRvhDD52SKvbheeTJUm6Ehkz
6101b9f0d904a708e900a74abc16d1e0eda67264Mark Andrews dnssec-enable yes;
2895f101b5585a19015ac2c2c1e1812ac467fa12Automatic Updater dnssec-validation yes;
2895f101b5585a19015ac2c2c1e1812ac467fa12Automatic Updater<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
2895f101b5585a19015ac2c2c1e1812ac467fa12Automatic Updater None of the keys listed in this example are valid. In particular,
2895f101b5585a19015ac2c2c1e1812ac467fa12Automatic Updater the root key is not valid.
6101b9f0d904a708e900a74abc16d1e0eda67264Mark Andrews When DNSSEC validation is enabled and properly configured,
71c66a876ecca77923638d3f94cc0783152b2f03Mark Andrews the resolver will reject any answers from signed, secure zones
6101b9f0d904a708e900a74abc16d1e0eda67264Mark Andrews which fail to validate, and will return SERVFAIL to the client.
6101b9f0d904a708e900a74abc16d1e0eda67264Mark Andrews Responses may fail to validate for any of several reasons,
6101b9f0d904a708e900a74abc16d1e0eda67264Mark Andrews including missing, expired, or invalid signatures, a key which
6101b9f0d904a708e900a74abc16d1e0eda67264Mark Andrews does not match the DS RRset in the parent zone, or an insecure
d3907d27cc138f45772d3d63082ae02c7659148aAutomatic Updater response from a zone which, according to its parent, should have
6101b9f0d904a708e900a74abc16d1e0eda67264Mark Andrews been secure.
6101b9f0d904a708e900a74abc16d1e0eda67264Mark Andrews<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
6101b9f0d904a708e900a74abc16d1e0eda67264Mark Andrews When the validator receives a response from an unsigned zone
6101b9f0d904a708e900a74abc16d1e0eda67264Mark Andrews that has a signed parent, it must confirm with the parent
6101b9f0d904a708e900a74abc16d1e0eda67264Mark Andrews that the zone was intentionally left unsigned. It does
2895f101b5585a19015ac2c2c1e1812ac467fa12Automatic Updater this by verifying, via signed and validated NSEC/NSEC3 records,
6101b9f0d904a708e900a74abc16d1e0eda67264Mark Andrews that the parent zone contains no DS records for the child.
2895f101b5585a19015ac2c2c1e1812ac467fa12Automatic Updater If the validator <span class="emphasis"><em>can</em></span> prove that the zone
2895f101b5585a19015ac2c2c1e1812ac467fa12Automatic Updater is insecure, then the response is accepted. However, if it
2895f101b5585a19015ac2c2c1e1812ac467fa12Automatic Updater cannot, then it must assume an insecure response to be a
2895f101b5585a19015ac2c2c1e1812ac467fa12Automatic Updater forgery; it rejects the response and logs an error.
2895f101b5585a19015ac2c2c1e1812ac467fa12Automatic Updater The logged error reads "insecurity proof failed" and
2895f101b5585a19015ac2c2c1e1812ac467fa12Automatic Updater "got insecure response; parent indicates it should be secure".
2895f101b5585a19015ac2c2c1e1812ac467fa12Automatic Updater (Prior to BIND 9.7, the logged error was "not insecure".
6101b9f0d904a708e900a74abc16d1e0eda67264Mark Andrews This referred to the zone, not the response.)
2895f101b5585a19015ac2c2c1e1812ac467fa12Automatic Updater<div class="titlepage"><div><div><h2 class="title" style="clear: both">
2895f101b5585a19015ac2c2c1e1812ac467fa12Automatic Updater<a name="id2572242"></a>IPv6 Support in <acronym class="acronym">BIND</acronym> 9</h2></div></div></div>
2895f101b5585a19015ac2c2c1e1812ac467fa12Automatic Updater <acronym class="acronym">BIND</acronym> 9 fully supports all currently
2895f101b5585a19015ac2c2c1e1812ac467fa12Automatic Updater defined forms of IPv6 name to address and address to name
2895f101b5585a19015ac2c2c1e1812ac467fa12Automatic Updater lookups. It will also use IPv6 addresses to make queries when
2895f101b5585a19015ac2c2c1e1812ac467fa12Automatic Updater running on an IPv6 capable system.
2895f101b5585a19015ac2c2c1e1812ac467fa12Automatic Updater For forward lookups, <acronym class="acronym">BIND</acronym> 9 supports
2895f101b5585a19015ac2c2c1e1812ac467fa12Automatic Updater only AAAA records. RFC 3363 deprecated the use of A6 records,
2895f101b5585a19015ac2c2c1e1812ac467fa12Automatic Updater and client-side support for A6 records was accordingly removed
2895f101b5585a19015ac2c2c1e1812ac467fa12Automatic Updater from <acronym class="acronym">BIND</acronym> 9.
2895f101b5585a19015ac2c2c1e1812ac467fa12Automatic Updater However, authoritative <acronym class="acronym">BIND</acronym> 9 name servers still
2895f101b5585a19015ac2c2c1e1812ac467fa12Automatic Updater load zone files containing A6 records correctly, answer queries
2895f101b5585a19015ac2c2c1e1812ac467fa12Automatic Updater for A6 records, and accept zone transfer for a zone containing A6
2895f101b5585a19015ac2c2c1e1812ac467fa12Automatic Updater For IPv6 reverse lookups, <acronym class="acronym">BIND</acronym> 9 supports
2895f101b5585a19015ac2c2c1e1812ac467fa12Automatic Updater the traditional "nibble" format used in the
2895f101b5585a19015ac2c2c1e1812ac467fa12Automatic Updater <span class="emphasis"><em>ip6.arpa</em></span> domain, as well as the older, deprecated
2895f101b5585a19015ac2c2c1e1812ac467fa12Automatic Updater <span class="emphasis"><em>ip6.int</em></span> domain.
2895f101b5585a19015ac2c2c1e1812ac467fa12Automatic Updater Older versions of <acronym class="acronym">BIND</acronym> 9
6101b9f0d904a708e900a74abc16d1e0eda67264Mark Andrews supported the "binary label" (also known as "bitstring") format,
6101b9f0d904a708e900a74abc16d1e0eda67264Mark Andrews but support of binary labels has been completely removed per
6101b9f0d904a708e900a74abc16d1e0eda67264Mark Andrews Many applications in <acronym class="acronym">BIND</acronym> 9 do not understand
6101b9f0d904a708e900a74abc16d1e0eda67264Mark Andrews the binary label format at all any more, and will return an
6101b9f0d904a708e900a74abc16d1e0eda67264Mark Andrews error if given.
6101b9f0d904a708e900a74abc16d1e0eda67264Mark Andrews In particular, an authoritative <acronym class="acronym">BIND</acronym> 9
6101b9f0d904a708e900a74abc16d1e0eda67264Mark Andrews name server will not load a zone file containing binary labels.
47012ae6dbf18a2503d7b33c1c9583dc38625cb7Mark Andrews For an overview of the format and structure of IPv6 addresses,
6101b9f0d904a708e900a74abc16d1e0eda67264Mark Andrews see <a href="Bv9ARM.ch09.html#ipv6addresses" title="IPv6 addresses (AAAA)">the section called “IPv6 addresses (AAAA)”</a>.
cbf7f1435f332b31f51a98611ccbfcd07c42c032Automatic Updater<div class="titlepage"><div><div><h3 class="title">
cbf7f1435f332b31f51a98611ccbfcd07c42c032Automatic Updater<a name="id2572304"></a>Address Lookups Using AAAA Records</h3></div></div></div>
cbf7f1435f332b31f51a98611ccbfcd07c42c032Automatic Updater The IPv6 AAAA record is a parallel to the IPv4 A record,
cbf7f1435f332b31f51a98611ccbfcd07c42c032Automatic Updater and, unlike the deprecated A6 record, specifies the entire
cbf7f1435f332b31f51a98611ccbfcd07c42c032Automatic Updater IPv6 address in a single record. For example,
cbf7f1435f332b31f51a98611ccbfcd07c42c032Automatic Updaterhost 3600 IN AAAA 2001:db8::1
cbf7f1435f332b31f51a98611ccbfcd07c42c032Automatic Updater Use of IPv4-in-IPv6 mapped addresses is not recommended.
cbf7f1435f332b31f51a98611ccbfcd07c42c032Automatic Updater If a host has an IPv4 address, use an A record, not
cbf7f1435f332b31f51a98611ccbfcd07c42c032Automatic Updater a AAAA, with <code class="literal">::ffff:192.168.42.1</code> as
cbf7f1435f332b31f51a98611ccbfcd07c42c032Automatic Updater<div class="titlepage"><div><div><h3 class="title">
cbf7f1435f332b31f51a98611ccbfcd07c42c032Automatic Updater<a name="id2572325"></a>Address to Name Lookups Using Nibble Format</h3></div></div></div>
cbf7f1435f332b31f51a98611ccbfcd07c42c032Automatic Updater When looking up an address in nibble format, the address
cbf7f1435f332b31f51a98611ccbfcd07c42c032Automatic Updater components are simply reversed, just as in IPv4, and
cbf7f1435f332b31f51a98611ccbfcd07c42c032Automatic Updater <code class="literal">ip6.arpa.</code> is appended to the
cbf7f1435f332b31f51a98611ccbfcd07c42c032Automatic Updater resulting name.
cbf7f1435f332b31f51a98611ccbfcd07c42c032Automatic Updater For example, the following would provide reverse name lookup for
cbf7f1435f332b31f51a98611ccbfcd07c42c032Automatic Updater a host with address
cbf7f1435f332b31f51a98611ccbfcd07c42c032Automatic Updater$ORIGIN 0.0.0.0.0.0.0.0.8.b.d.0.1.0.0.2.ip6.arpa.
cbf7f1435f332b31f51a98611ccbfcd07c42c032Automatic Updater1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0 14400 IN PTR (
6f64d4ab8e68f9b2333bcbfc755396d29a4a9d7cAutomatic Updater<table width="100%" summary="Navigation footer">
6f64d4ab8e68f9b2333bcbfc755396d29a4a9d7cAutomatic Updater<a accesskey="p" href="Bv9ARM.ch03.html">Prev</a>�</td>
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