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42 <div class="chapter" lang="en">
43 <div class="titlepage"><div><div><h2 class="title">
44 <a name="Bv9ARM.ch04"></a>Chapter 4. Advanced DNS Features</h2></div></div></div>
46 <p><b>Table of Contents</b></p>
48 <dt><span class="sect1"><a href="Bv9ARM.ch04.html#notify">Notify</a></span></dt>
49 <dt><span class="sect1"><a href="Bv9ARM.ch04.html#dynamic_update">Dynamic Update</a></span></dt>
50 <dd><dl><dt><span class="sect2"><a href="Bv9ARM.ch04.html#journal">The journal file</a></span></dt></dl></dd>
51 <dt><span class="sect1"><a href="Bv9ARM.ch04.html#incremental_zone_transfers">Incremental Zone Transfers (IXFR)</a></span></dt>
52 <dt><span class="sect1"><a href="Bv9ARM.ch04.html#id2570825">Split DNS</a></span></dt>
53 <dd><dl><dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2570843">Example split DNS setup</a></span></dt></dl></dd>
54 <dt><span class="sect1"><a href="Bv9ARM.ch04.html#tsig">TSIG</a></span></dt>
56 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2571345">Generate Shared Keys for Each Pair of Hosts</a></span></dt>
57 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2571555">Copying the Shared Secret to Both Machines</a></span></dt>
58 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2571565">Informing the Servers of the Key's Existence</a></span></dt>
59 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2571602">Instructing the Server to Use the Key</a></span></dt>
60 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2571659">TSIG Key Based Access Control</a></span></dt>
61 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2571708">Errors</a></span></dt>
63 <dt><span class="sect1"><a href="Bv9ARM.ch04.html#id2571722">TKEY</a></span></dt>
64 <dt><span class="sect1"><a href="Bv9ARM.ch04.html#id2563989">SIG(0)</a></span></dt>
65 <dt><span class="sect1"><a href="Bv9ARM.ch04.html#DNSSEC">DNSSEC</a></span></dt>
67 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2564057">Generating Keys</a></span></dt>
68 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2572192">Signing the Zone</a></span></dt>
69 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2572273">Configuring Servers</a></span></dt>
71 <dt><span class="sect1"><a href="Bv9ARM.ch04.html#dnssec.dynamic.zones">DNSSEC, Dynamic Zones, and Automatic Signing</a></span></dt>
73 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2563485">Converting from insecure to secure</a></span></dt>
74 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2563523">Dynamic DNS update method</a></span></dt>
75 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2563627">Fully automatic zone signing</a></span></dt>
76 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2563709">Private-type records</a></span></dt>
77 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2563747">DNSKEY rollovers</a></span></dt>
78 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2563828">Dynamic DNS update method</a></span></dt>
79 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2563861">Automatic key rollovers</a></span></dt>
80 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2563888">NSEC3PARAM rollovers via UPDATE</a></span></dt>
81 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2571816">Converting from NSEC to NSEC3</a></span></dt>
82 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2571826">Converting from NSEC3 to NSEC</a></span></dt>
83 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2571838">Converting from secure to insecure</a></span></dt>
84 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2571876">Periodic re-signing</a></span></dt>
85 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2572022">NSEC3 and OPTOUT</a></span></dt>
87 <dt><span class="sect1"><a href="Bv9ARM.ch04.html#rfc5011.support">Dynamic Trust Anchor Management</a></span></dt>
89 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2572075">Validating Resolver</a></span></dt>
90 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2605958">Authoritative Server</a></span></dt>
92 <dt><span class="sect1"><a href="Bv9ARM.ch04.html#pkcs11">PKCS #11 (Cryptoki) support</a></span></dt>
94 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2608598">Prerequisites</a></span></dt>
95 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2607026">Building BIND 9 with PKCS#11</a></span></dt>
96 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2607121">PKCS #11 Tools</a></span></dt>
97 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2607152">Using the HSM</a></span></dt>
98 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2608784">Specifying the engine on the command line</a></span></dt>
99 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2609239">Running named with automatic zone re-signing</a></span></dt>
101 <dt><span class="sect1"><a href="Bv9ARM.ch04.html#id2572468">IPv6 Support in <acronym class="acronym">BIND</acronym> 9</a></span></dt>
103 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2572734">Address Lookups Using AAAA Records</a></span></dt>
104 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2572756">Address to Name Lookups Using Nibble Format</a></span></dt>
108 <div class="sect1" lang="en">
109 <div class="titlepage"><div><div><h2 class="title" style="clear: both">
110 <a name="notify"></a>Notify</h2></div></div></div>
112 <acronym class="acronym">DNS</acronym> NOTIFY is a mechanism that allows master
113 servers to notify their slave servers of changes to a zone's data. In
114 response to a <span><strong class="command">NOTIFY</strong></span> from a master server, the
115 slave will check to see that its version of the zone is the
116 current version and, if not, initiate a zone transfer.
119 For more information about <acronym class="acronym">DNS</acronym>
120 <span><strong class="command">NOTIFY</strong></span>, see the description of the
121 <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
122 the description of the zone option <span><strong class="command">also-notify</strong></span> in
123 <a href="Bv9ARM.ch06.html#zone_transfers" title="Zone Transfers">the section called “Zone Transfers”</a>. The <span><strong class="command">NOTIFY</strong></span>
124 protocol is specified in RFC 1996.
126 <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
127 <h3 class="title">Note</h3>
128 As a slave zone can also be a master to other slaves, <span><strong class="command">named</strong></span>,
129 by default, sends <span><strong class="command">NOTIFY</strong></span> messages for every zone
130 it loads. Specifying <span><strong class="command">notify master-only;</strong></span> will
131 cause <span><strong class="command">named</strong></span> to only send <span><strong class="command">NOTIFY</strong></span> for master
135 <div class="sect1" lang="en">
136 <div class="titlepage"><div><div><h2 class="title" style="clear: both">
137 <a name="dynamic_update"></a>Dynamic Update</h2></div></div></div>
139 Dynamic Update is a method for adding, replacing or deleting
140 records in a master server by sending it a special form of DNS
141 messages. The format and meaning of these messages is specified
145 Dynamic update is enabled by including an
146 <span><strong class="command">allow-update</strong></span> or an <span><strong class="command">update-policy</strong></span>
147 clause in the <span><strong class="command">zone</strong></span> statement.
150 If the zone's <span><strong class="command">update-policy</strong></span> is set to
151 <strong class="userinput"><code>local</code></strong>, updates to the zone
152 will be permitted for the key <code class="varname">local-ddns</code>,
153 which will be generated by <span><strong class="command">named</strong></span> at startup.
154 See <a href="Bv9ARM.ch06.html#dynamic_update_policies" title="Dynamic Update Policies">the section called “Dynamic Update Policies”</a> for more details.
157 The <span><strong class="command">tkey-gssapi-credential</strong></span> and
158 <span><strong class="command">tkey-domain</strong></span> clauses in the
159 <span><strong class="command">options</strong></span> statement enable the
160 server to negotiate keys that can be matched against those
161 in <span><strong class="command">update-policy</strong></span> or
162 <span><strong class="command">allow-update</strong></span>.
165 Updating of secure zones (zones using DNSSEC) follows RFC
166 3007: RRSIG, NSEC and NSEC3 records affected by updates are
167 automatically regenerated by the server using an online
168 zone key. Update authorization is based on transaction
169 signatures and an explicit server policy.
171 <div class="sect2" lang="en">
172 <div class="titlepage"><div><div><h3 class="title">
173 <a name="journal"></a>The journal file</h3></div></div></div>
175 All changes made to a zone using dynamic update are stored
176 in the zone's journal file. This file is automatically created
177 by the server when the first dynamic update takes place.
178 The name of the journal file is formed by appending the extension
179 <code class="filename">.jnl</code> to the name of the
181 file unless specifically overridden. The journal file is in a
182 binary format and should not be edited manually.
185 The server will also occasionally write ("dump")
186 the complete contents of the updated zone to its zone file.
187 This is not done immediately after
188 each dynamic update, because that would be too slow when a large
189 zone is updated frequently. Instead, the dump is delayed by
190 up to 15 minutes, allowing additional updates to take place.
191 During the dump process, transient files will be created
192 with the extensions <code class="filename">.jnw</code> and
193 <code class="filename">.jbk</code>; under ordinary circumstances, these
194 will be removed when the dump is complete, and can be safely
198 When a server is restarted after a shutdown or crash, it will replay
199 the journal file to incorporate into the zone any updates that
201 place after the last zone dump.
204 Changes that result from incoming incremental zone transfers are
206 journalled in a similar way.
209 The zone files of dynamic zones cannot normally be edited by
210 hand because they are not guaranteed to contain the most recent
211 dynamic changes — those are only in the journal file.
212 The only way to ensure that the zone file of a dynamic zone
213 is up to date is to run <span><strong class="command">rndc stop</strong></span>.
216 If you have to make changes to a dynamic zone
217 manually, the following procedure will work: Disable dynamic updates
219 <span><strong class="command">rndc freeze <em class="replaceable"><code>zone</code></em></strong></span>.
220 This will also remove the zone's <code class="filename">.jnl</code> file
221 and update the master file. Edit the zone file. Run
222 <span><strong class="command">rndc thaw <em class="replaceable"><code>zone</code></em></strong></span>
223 to reload the changed zone and re-enable dynamic updates.
227 <div class="sect1" lang="en">
228 <div class="titlepage"><div><div><h2 class="title" style="clear: both">
229 <a name="incremental_zone_transfers"></a>Incremental Zone Transfers (IXFR)</h2></div></div></div>
231 The incremental zone transfer (IXFR) protocol is a way for
232 slave servers to transfer only changed data, instead of having to
233 transfer the entire zone. The IXFR protocol is specified in RFC
234 1995. See <a href="Bv9ARM.ch09.html#proposed_standards">Proposed Standards</a>.
237 When acting as a master, <acronym class="acronym">BIND</acronym> 9
238 supports IXFR for those zones
239 where the necessary change history information is available. These
240 include master zones maintained by dynamic update and slave zones
241 whose data was obtained by IXFR. For manually maintained master
242 zones, and for slave zones obtained by performing a full zone
243 transfer (AXFR), IXFR is supported only if the option
244 <span><strong class="command">ixfr-from-differences</strong></span> is set
245 to <strong class="userinput"><code>yes</code></strong>.
248 When acting as a slave, <acronym class="acronym">BIND</acronym> 9 will
249 attempt to use IXFR unless
250 it is explicitly disabled. For more information about disabling
251 IXFR, see the description of the <span><strong class="command">request-ixfr</strong></span> clause
252 of the <span><strong class="command">server</strong></span> statement.
255 <div class="sect1" lang="en">
256 <div class="titlepage"><div><div><h2 class="title" style="clear: both">
257 <a name="id2570825"></a>Split DNS</h2></div></div></div>
259 Setting up different views, or visibility, of the DNS space to
260 internal and external resolvers is usually referred to as a
261 <span class="emphasis"><em>Split DNS</em></span> setup. There are several
262 reasons an organization would want to set up its DNS this way.
265 One common reason for setting up a DNS system this way is
266 to hide "internal" DNS information from "external" clients on the
267 Internet. There is some debate as to whether or not this is actually
269 Internal DNS information leaks out in many ways (via email headers,
270 for example) and most savvy "attackers" can find the information
271 they need using other means.
272 However, since listing addresses of internal servers that
273 external clients cannot possibly reach can result in
274 connection delays and other annoyances, an organization may
275 choose to use a Split DNS to present a consistent view of itself
276 to the outside world.
279 Another common reason for setting up a Split DNS system is
280 to allow internal networks that are behind filters or in RFC 1918
281 space (reserved IP space, as documented in RFC 1918) to resolve DNS
282 on the Internet. Split DNS can also be used to allow mail from outside
283 back in to the internal network.
285 <div class="sect2" lang="en">
286 <div class="titlepage"><div><div><h3 class="title">
287 <a name="id2570843"></a>Example split DNS setup</h3></div></div></div>
289 Let's say a company named <span class="emphasis"><em>Example, Inc.</em></span>
290 (<code class="literal">example.com</code>)
291 has several corporate sites that have an internal network with
293 Internet Protocol (IP) space and an external demilitarized zone (DMZ),
294 or "outside" section of a network, that is available to the public.
297 <span class="emphasis"><em>Example, Inc.</em></span> wants its internal clients
298 to be able to resolve external hostnames and to exchange mail with
299 people on the outside. The company also wants its internal resolvers
300 to have access to certain internal-only zones that are not available
301 at all outside of the internal network.
304 In order to accomplish this, the company will set up two sets
305 of name servers. One set will be on the inside network (in the
307 IP space) and the other set will be on bastion hosts, which are
309 hosts that can talk to both sides of its network, in the DMZ.
312 The internal servers will be configured to forward all queries,
313 except queries for <code class="filename">site1.internal</code>, <code class="filename">site2.internal</code>, <code class="filename">site1.example.com</code>,
314 and <code class="filename">site2.example.com</code>, to the servers
316 DMZ. These internal servers will have complete sets of information
317 for <code class="filename">site1.example.com</code>, <code class="filename">site2.example.com</code>, <code class="filename">site1.internal</code>,
318 and <code class="filename">site2.internal</code>.
321 To protect the <code class="filename">site1.internal</code> and <code class="filename">site2.internal</code> domains,
322 the internal name servers must be configured to disallow all queries
323 to these domains from any external hosts, including the bastion
327 The external servers, which are on the bastion hosts, will
328 be configured to serve the "public" version of the <code class="filename">site1</code> and <code class="filename">site2.example.com</code> zones.
329 This could include things such as the host records for public servers
330 (<code class="filename">www.example.com</code> and <code class="filename">ftp.example.com</code>),
331 and mail exchange (MX) records (<code class="filename">a.mx.example.com</code> and <code class="filename">b.mx.example.com</code>).
334 In addition, the public <code class="filename">site1</code> and <code class="filename">site2.example.com</code> zones
335 should have special MX records that contain wildcard (`*') records
336 pointing to the bastion hosts. This is needed because external mail
337 servers do not have any other way of looking up how to deliver mail
338 to those internal hosts. With the wildcard records, the mail will
339 be delivered to the bastion host, which can then forward it on to
343 Here's an example of a wildcard MX record:
345 <pre class="programlisting">* IN MX 10 external1.example.com.</pre>
347 Now that they accept mail on behalf of anything in the internal
348 network, the bastion hosts will need to know how to deliver mail
349 to internal hosts. In order for this to work properly, the resolvers
351 the bastion hosts will need to be configured to point to the internal
352 name servers for DNS resolution.
355 Queries for internal hostnames will be answered by the internal
356 servers, and queries for external hostnames will be forwarded back
357 out to the DNS servers on the bastion hosts.
360 In order for all this to work properly, internal clients will
361 need to be configured to query <span class="emphasis"><em>only</em></span> the internal
362 name servers for DNS queries. This could also be enforced via
364 filtering on the network.
367 If everything has been set properly, <span class="emphasis"><em>Example, Inc.</em></span>'s
368 internal clients will now be able to:
370 <div class="itemizedlist"><ul type="disc">
372 Look up any hostnames in the <code class="literal">site1</code>
374 <code class="literal">site2.example.com</code> zones.
377 Look up any hostnames in the <code class="literal">site1.internal</code> and
378 <code class="literal">site2.internal</code> domains.
380 <li>Look up any hostnames on the Internet.</li>
381 <li>Exchange mail with both internal and external people.</li>
384 Hosts on the Internet will be able to:
386 <div class="itemizedlist"><ul type="disc">
388 Look up any hostnames in the <code class="literal">site1</code>
390 <code class="literal">site2.example.com</code> zones.
393 Exchange mail with anyone in the <code class="literal">site1</code> and
394 <code class="literal">site2.example.com</code> zones.
398 Here is an example configuration for the setup we just
399 described above. Note that this is only configuration information;
400 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>.
403 Internal DNS server config:
405 <pre class="programlisting">
407 acl internals { 172.16.72.0/24; 192.168.1.0/24; };
409 acl externals { <code class="varname">bastion-ips-go-here</code>; };
415 // forward to external servers
417 <code class="varname">bastion-ips-go-here</code>;
419 // sample allow-transfer (no one)
420 allow-transfer { none; };
421 // restrict query access
422 allow-query { internals; externals; };
423 // restrict recursion
424 allow-recursion { internals; };
429 // sample master zone
430 zone "site1.example.com" {
432 file "m/site1.example.com";
433 // do normal iterative resolution (do not forward)
435 allow-query { internals; externals; };
436 allow-transfer { internals; };
440 zone "site2.example.com" {
442 file "s/site2.example.com";
443 masters { 172.16.72.3; };
445 allow-query { internals; externals; };
446 allow-transfer { internals; };
449 zone "site1.internal" {
451 file "m/site1.internal";
453 allow-query { internals; };
454 allow-transfer { internals; }
457 zone "site2.internal" {
459 file "s/site2.internal";
460 masters { 172.16.72.3; };
462 allow-query { internals };
463 allow-transfer { internals; }
467 External (bastion host) DNS server config:
469 <pre class="programlisting">
470 acl internals { 172.16.72.0/24; 192.168.1.0/24; };
472 acl externals { bastion-ips-go-here; };
477 // sample allow-transfer (no one)
478 allow-transfer { none; };
479 // default query access
480 allow-query { any; };
481 // restrict cache access
482 allow-query-cache { internals; externals; };
483 // restrict recursion
484 allow-recursion { internals; externals; };
490 zone "site1.example.com" {
492 file "m/site1.foo.com";
493 allow-transfer { internals; externals; };
496 zone "site2.example.com" {
498 file "s/site2.foo.com";
499 masters { another_bastion_host_maybe; };
500 allow-transfer { internals; externals; }
504 In the <code class="filename">resolv.conf</code> (or equivalent) on
507 <pre class="programlisting">
509 nameserver 172.16.72.2
510 nameserver 172.16.72.3
511 nameserver 172.16.72.4
515 <div class="sect1" lang="en">
516 <div class="titlepage"><div><div><h2 class="title" style="clear: both">
517 <a name="tsig"></a>TSIG</h2></div></div></div>
519 This is a short guide to setting up Transaction SIGnatures
520 (TSIG) based transaction security in <acronym class="acronym">BIND</acronym>. It describes changes
521 to the configuration file as well as what changes are required for
522 different features, including the process of creating transaction
523 keys and using transaction signatures with <acronym class="acronym">BIND</acronym>.
526 <acronym class="acronym">BIND</acronym> primarily supports TSIG for server
527 to server communication.
528 This includes zone transfer, notify, and recursive query messages.
529 Resolvers based on newer versions of <acronym class="acronym">BIND</acronym> 8 have limited support
533 TSIG can also be useful for dynamic update. A primary
534 server for a dynamic zone should control access to the dynamic
535 update service, but IP-based access control is insufficient.
536 The cryptographic access control provided by TSIG
537 is far superior. The <span><strong class="command">nsupdate</strong></span>
538 program supports TSIG via the <code class="option">-k</code> and
539 <code class="option">-y</code> command line options or inline by use
540 of the <span><strong class="command">key</strong></span>.
542 <div class="sect2" lang="en">
543 <div class="titlepage"><div><div><h3 class="title">
544 <a name="id2571345"></a>Generate Shared Keys for Each Pair of Hosts</h3></div></div></div>
546 A shared secret is generated to be shared between <span class="emphasis"><em>host1</em></span> and <span class="emphasis"><em>host2</em></span>.
547 An arbitrary key name is chosen: "host1-host2.". The key name must
548 be the same on both hosts.
550 <div class="sect3" lang="en">
551 <div class="titlepage"><div><div><h4 class="title">
552 <a name="id2571362"></a>Automatic Generation</h4></div></div></div>
554 The following command will generate a 128-bit (16 byte) HMAC-SHA256
555 key as described above. Longer keys are better, but shorter keys
556 are easier to read. Note that the maximum key length is the digest
557 length, here 256 bits.
560 <strong class="userinput"><code>dnssec-keygen -a hmac-sha256 -b 128 -n HOST host1-host2.</code></strong>
563 The key is in the file <code class="filename">Khost1-host2.+163+00000.private</code>.
564 Nothing directly uses this file, but the base-64 encoded string
565 following "<code class="literal">Key:</code>"
566 can be extracted from the file and used as a shared secret:
568 <pre class="programlisting">Key: La/E5CjG9O+os1jq0a2jdA==</pre>
570 The string "<code class="literal">La/E5CjG9O+os1jq0a2jdA==</code>" can
571 be used as the shared secret.
574 <div class="sect3" lang="en">
575 <div class="titlepage"><div><div><h4 class="title">
576 <a name="id2571537"></a>Manual Generation</h4></div></div></div>
578 The shared secret is simply a random sequence of bits, encoded
579 in base-64. Most ASCII strings are valid base-64 strings (assuming
580 the length is a multiple of 4 and only valid characters are used),
581 so the shared secret can be manually generated.
584 Also, a known string can be run through <span><strong class="command">mmencode</strong></span> or
585 a similar program to generate base-64 encoded data.
589 <div class="sect2" lang="en">
590 <div class="titlepage"><div><div><h3 class="title">
591 <a name="id2571555"></a>Copying the Shared Secret to Both Machines</h3></div></div></div>
593 This is beyond the scope of DNS. A secure transport mechanism
594 should be used. This could be secure FTP, ssh, telephone, etc.
597 <div class="sect2" lang="en">
598 <div class="titlepage"><div><div><h3 class="title">
599 <a name="id2571565"></a>Informing the Servers of the Key's Existence</h3></div></div></div>
601 Imagine <span class="emphasis"><em>host1</em></span> and <span class="emphasis"><em>host 2</em></span>
603 both servers. The following is added to each server's <code class="filename">named.conf</code> file:
605 <pre class="programlisting">
607 algorithm hmac-sha256;
608 secret "La/E5CjG9O+os1jq0a2jdA==";
612 The secret is the one generated above. Since this is a secret, it
613 is recommended that either <code class="filename">named.conf</code> be
614 non-world readable, or the key directive be added to a non-world
615 readable file that is included by <code class="filename">named.conf</code>.
618 At this point, the key is recognized. This means that if the
619 server receives a message signed by this key, it can verify the
620 signature. If the signature is successfully verified, the
621 response is signed by the same key.
624 <div class="sect2" lang="en">
625 <div class="titlepage"><div><div><h3 class="title">
626 <a name="id2571602"></a>Instructing the Server to Use the Key</h3></div></div></div>
628 Since keys are shared between two hosts only, the server must
629 be told when keys are to be used. The following is added to the <code class="filename">named.conf</code> file
630 for <span class="emphasis"><em>host1</em></span>, if the IP address of <span class="emphasis"><em>host2</em></span> is
633 <pre class="programlisting">
635 keys { host1-host2. ;};
639 Multiple keys may be present, but only the first is used.
640 This directive does not contain any secrets, so it may be in a
645 If <span class="emphasis"><em>host1</em></span> sends a message that is a request
646 to that address, the message will be signed with the specified key. <span class="emphasis"><em>host1</em></span> will
647 expect any responses to signed messages to be signed with the same
651 A similar statement must be present in <span class="emphasis"><em>host2</em></span>'s
652 configuration file (with <span class="emphasis"><em>host1</em></span>'s address) for <span class="emphasis"><em>host2</em></span> to
653 sign request messages to <span class="emphasis"><em>host1</em></span>.
656 <div class="sect2" lang="en">
657 <div class="titlepage"><div><div><h3 class="title">
658 <a name="id2571659"></a>TSIG Key Based Access Control</h3></div></div></div>
660 <acronym class="acronym">BIND</acronym> allows IP addresses and ranges
661 to be specified in ACL
663 <span><strong class="command">allow-{ query | transfer | update }</strong></span>
665 This has been extended to allow TSIG keys also. The above key would
666 be denoted <span><strong class="command">key host1-host2.</strong></span>
669 An example of an <span><strong class="command">allow-update</strong></span> directive would be:
671 <pre class="programlisting">
672 allow-update { key host1-host2. ;};
675 This allows dynamic updates to succeed only if the request
676 was signed by a key named "<span><strong class="command">host1-host2.</strong></span>".
679 See <a href="Bv9ARM.ch06.html#dynamic_update_policies" title="Dynamic Update Policies">the section called “Dynamic Update Policies”</a> for a discussion of
680 the more flexible <span><strong class="command">update-policy</strong></span> statement.
683 <div class="sect2" lang="en">
684 <div class="titlepage"><div><div><h3 class="title">
685 <a name="id2571708"></a>Errors</h3></div></div></div>
687 The processing of TSIG signed messages can result in
688 several errors. If a signed message is sent to a non-TSIG aware
689 server, a FORMERR (format error) will be returned, since the server will not
690 understand the record. This is a result of misconfiguration,
691 since the server must be explicitly configured to send a TSIG
692 signed message to a specific server.
695 If a TSIG aware server receives a message signed by an
696 unknown key, the response will be unsigned with the TSIG
697 extended error code set to BADKEY. If a TSIG aware server
698 receives a message with a signature that does not validate, the
699 response will be unsigned with the TSIG extended error code set
700 to BADSIG. If a TSIG aware server receives a message with a time
701 outside of the allowed range, the response will be signed with
702 the TSIG extended error code set to BADTIME, and the time values
703 will be adjusted so that the response can be successfully
704 verified. In any of these cases, the message's rcode (response code) is set to
705 NOTAUTH (not authenticated).
709 <div class="sect1" lang="en">
710 <div class="titlepage"><div><div><h2 class="title" style="clear: both">
711 <a name="id2571722"></a>TKEY</h2></div></div></div>
712 <p><span><strong class="command">TKEY</strong></span>
713 is a mechanism for automatically generating a shared secret
714 between two hosts. There are several "modes" of
715 <span><strong class="command">TKEY</strong></span> that specify how the key is generated
716 or assigned. <acronym class="acronym">BIND</acronym> 9 implements only one of
717 these modes, the Diffie-Hellman key exchange. Both hosts are
718 required to have a Diffie-Hellman KEY record (although this
719 record is not required to be present in a zone). The
720 <span><strong class="command">TKEY</strong></span> process must use signed messages,
721 signed either by TSIG or SIG(0). The result of
722 <span><strong class="command">TKEY</strong></span> is a shared secret that can be used to
723 sign messages with TSIG. <span><strong class="command">TKEY</strong></span> can also be
724 used to delete shared secrets that it had previously
728 The <span><strong class="command">TKEY</strong></span> process is initiated by a
730 or server by sending a signed <span><strong class="command">TKEY</strong></span>
732 (including any appropriate KEYs) to a TKEY-aware server. The
733 server response, if it indicates success, will contain a
734 <span><strong class="command">TKEY</strong></span> record and any appropriate keys.
736 this exchange, both participants have enough information to
737 determine the shared secret; the exact process depends on the
738 <span><strong class="command">TKEY</strong></span> mode. When using the
740 <span><strong class="command">TKEY</strong></span> mode, Diffie-Hellman keys are
742 and the shared secret is derived by both participants.
745 <div class="sect1" lang="en">
746 <div class="titlepage"><div><div><h2 class="title" style="clear: both">
747 <a name="id2563989"></a>SIG(0)</h2></div></div></div>
749 <acronym class="acronym">BIND</acronym> 9 partially supports DNSSEC SIG(0)
750 transaction signatures as specified in RFC 2535 and RFC 2931.
752 uses public/private keys to authenticate messages. Access control
753 is performed in the same manner as TSIG keys; privileges can be
754 granted or denied based on the key name.
757 When a SIG(0) signed message is received, it will only be
758 verified if the key is known and trusted by the server; the server
759 will not attempt to locate and/or validate the key.
762 SIG(0) signing of multiple-message TCP streams is not
766 The only tool shipped with <acronym class="acronym">BIND</acronym> 9 that
767 generates SIG(0) signed messages is <span><strong class="command">nsupdate</strong></span>.
770 <div class="sect1" lang="en">
771 <div class="titlepage"><div><div><h2 class="title" style="clear: both">
772 <a name="DNSSEC"></a>DNSSEC</h2></div></div></div>
774 Cryptographic authentication of DNS information is possible
775 through the DNS Security (<span class="emphasis"><em>DNSSEC-bis</em></span>) extensions,
776 defined in RFC 4033, RFC 4034, and RFC 4035.
777 This section describes the creation and use of DNSSEC signed zones.
780 In order to set up a DNSSEC secure zone, there are a series
781 of steps which must be followed. <acronym class="acronym">BIND</acronym>
784 that are used in this process, which are explained in more detail
785 below. In all cases, the <code class="option">-h</code> option prints a
786 full list of parameters. Note that the DNSSEC tools require the
787 keyset files to be in the working directory or the
788 directory specified by the <code class="option">-d</code> option, and
789 that the tools shipped with BIND 9.2.x and earlier are not compatible
790 with the current ones.
793 There must also be communication with the administrators of
794 the parent and/or child zone to transmit keys. A zone's security
795 status must be indicated by the parent zone for a DNSSEC capable
796 resolver to trust its data. This is done through the presence
797 or absence of a <code class="literal">DS</code> record at the
802 For other servers to trust data in this zone, they must
803 either be statically configured with this zone's zone key or the
804 zone key of another zone above this one in the DNS tree.
806 <div class="sect2" lang="en">
807 <div class="titlepage"><div><div><h3 class="title">
808 <a name="id2564057"></a>Generating Keys</h3></div></div></div>
810 The <span><strong class="command">dnssec-keygen</strong></span> program is used to
814 A secure zone must contain one or more zone keys. The
815 zone keys will sign all other records in the zone, as well as
816 the zone keys of any secure delegated zones. Zone keys must
817 have the same name as the zone, a name type of
818 <span><strong class="command">ZONE</strong></span>, and must be usable for
820 It is recommended that zone keys use a cryptographic algorithm
821 designated as "mandatory to implement" by the IETF; currently
822 the only one is RSASHA1.
825 The following command will generate a 768-bit RSASHA1 key for
826 the <code class="filename">child.example</code> zone:
829 <strong class="userinput"><code>dnssec-keygen -a RSASHA1 -b 768 -n ZONE child.example.</code></strong>
832 Two output files will be produced:
833 <code class="filename">Kchild.example.+005+12345.key</code> and
834 <code class="filename">Kchild.example.+005+12345.private</code>
836 12345 is an example of a key tag). The key filenames contain
837 the key name (<code class="filename">child.example.</code>),
839 is DSA, 1 is RSAMD5, 5 is RSASHA1, etc.), and the key tag (12345 in
841 The private key (in the <code class="filename">.private</code>
843 used to generate signatures, and the public key (in the
844 <code class="filename">.key</code> file) is used for signature
848 To generate another key with the same properties (but with
849 a different key tag), repeat the above command.
852 The <span><strong class="command">dnssec-keyfromlabel</strong></span> program is used
853 to get a key pair from a crypto hardware and build the key
854 files. Its usage is similar to <span><strong class="command">dnssec-keygen</strong></span>.
857 The public keys should be inserted into the zone file by
858 including the <code class="filename">.key</code> files using
859 <span><strong class="command">$INCLUDE</strong></span> statements.
862 <div class="sect2" lang="en">
863 <div class="titlepage"><div><div><h3 class="title">
864 <a name="id2572192"></a>Signing the Zone</h3></div></div></div>
866 The <span><strong class="command">dnssec-signzone</strong></span> program is used
870 Any <code class="filename">keyset</code> files corresponding to
871 secure subzones should be present. The zone signer will
872 generate <code class="literal">NSEC</code>, <code class="literal">NSEC3</code>
873 and <code class="literal">RRSIG</code> records for the zone, as
874 well as <code class="literal">DS</code> for the child zones if
875 <code class="literal">'-g'</code> is specified. If <code class="literal">'-g'</code>
876 is not specified, then DS RRsets for the secure child
877 zones need to be added manually.
880 The following command signs the zone, assuming it is in a
881 file called <code class="filename">zone.child.example</code>. By
882 default, all zone keys which have an available private key are
883 used to generate signatures.
886 <strong class="userinput"><code>dnssec-signzone -o child.example zone.child.example</code></strong>
889 One output file is produced:
890 <code class="filename">zone.child.example.signed</code>. This
892 should be referenced by <code class="filename">named.conf</code>
894 input file for the zone.
896 <p><span><strong class="command">dnssec-signzone</strong></span>
897 will also produce a keyset and dsset files and optionally a
898 dlvset file. These are used to provide the parent zone
899 administrators with the <code class="literal">DNSKEYs</code> (or their
900 corresponding <code class="literal">DS</code> records) that are the
901 secure entry point to the zone.
904 <div class="sect2" lang="en">
905 <div class="titlepage"><div><div><h3 class="title">
906 <a name="id2572273"></a>Configuring Servers</h3></div></div></div>
908 To enable <span><strong class="command">named</strong></span> to respond appropriately
909 to DNS requests from DNSSEC aware clients,
910 <span><strong class="command">dnssec-enable</strong></span> must be set to yes.
911 (This is the default setting.)
914 To enable <span><strong class="command">named</strong></span> to validate answers from
915 other servers, the <span><strong class="command">dnssec-enable</strong></span> and
916 <span><strong class="command">dnssec-validation</strong></span> options must both be
917 set to yes (the default setting in <acronym class="acronym">BIND</acronym> 9.5
918 and later), and at least one trust anchor must be configured
919 with a <span><strong class="command">trusted-keys</strong></span> or
920 <span><strong class="command">managed-keys</strong></span> statement in
921 <code class="filename">named.conf</code>.
924 <span><strong class="command">trusted-keys</strong></span> are copies of DNSKEY RRs
925 for zones that are used to form the first link in the
926 cryptographic chain of trust. All keys listed in
927 <span><strong class="command">trusted-keys</strong></span> (and corresponding zones)
928 are deemed to exist and only the listed keys will be used
929 to validated the DNSKEY RRset that they are from.
932 <span><strong class="command">managed-keys</strong></span> are trusted keys which are
933 automatically kept up to date via RFC 5011 trust anchor
937 <span><strong class="command">trusted-keys</strong></span> and
938 <span><strong class="command">managed-keys</strong></span> are described in more detail
939 later in this document.
942 Unlike <acronym class="acronym">BIND</acronym> 8, <acronym class="acronym">BIND</acronym>
943 9 does not verify signatures on load, so zone keys for
944 authoritative zones do not need to be specified in the
948 After DNSSEC gets established, a typical DNSSEC configuration
949 will look something like the following. It has one or
950 more public keys for the root. This allows answers from
951 outside the organization to be validated. It will also
952 have several keys for parts of the namespace the organization
953 controls. These are here to ensure that <span><strong class="command">named</strong></span>
954 is immune to compromises in the DNSSEC components of the security
957 <pre class="programlisting">
960 "." initial-key 257 3 3 "BNY4wrWM1nCfJ+CXd0rVXyYmobt7sEEfK3clRbGaTwS
961 JxrGkxJWoZu6I7PzJu/E9gx4UC1zGAHlXKdE4zYIpRh
962 aBKnvcC2U9mZhkdUpd1Vso/HAdjNe8LmMlnzY3zy2Xy
963 4klWOADTPzSv9eamj8V18PHGjBLaVtYvk/ln5ZApjYg
964 hf+6fElrmLkdaz MQ2OCnACR817DF4BBa7UR/beDHyp
965 5iWTXWSi6XmoJLbG9Scqc7l70KDqlvXR3M/lUUVRbke
966 g1IPJSidmK3ZyCllh4XSKbje/45SKucHgnwU5jefMtq
967 66gKodQj+MiA21AfUVe7u99WzTLzY3qlxDhxYQQ20FQ
968 97S+LKUTpQcq27R7AT3/V5hRQxScINqwcz4jYqZD2fQ
969 dgxbcDTClU0CRBdiieyLMNzXG3";
973 /* Key for our organization's forward zone */
974 example.com. 257 3 5 "AwEAAaxPMcR2x0HbQV4WeZB6oEDX+r0QM6
975 5KbhTjrW1ZaARmPhEZZe3Y9ifgEuq7vZ/z
976 GZUdEGNWy+JZzus0lUptwgjGwhUS1558Hb
977 4JKUbbOTcM8pwXlj0EiX3oDFVmjHO444gL
978 kBOUKUf/mC7HvfwYH/Be22GnClrinKJp1O
979 g4ywzO9WglMk7jbfW33gUKvirTHr25GL7S
980 TQUzBb5Usxt8lgnyTUHs1t3JwCY5hKZ6Cq
981 FxmAVZP20igTixin/1LcrgX/KMEGd/biuv
982 F4qJCyduieHukuY3H4XMAcR+xia2nIUPvm
983 /oyWR8BW/hWdzOvnSCThlHf3xiYleDbt/o
986 /* Key for our reverse zone. */
987 2.0.192.IN-ADDRPA.NET. 257 3 5 "AQOnS4xn/IgOUpBPJ3bogzwc
988 xOdNax071L18QqZnQQQAVVr+i
989 LhGTnNGp3HoWQLUIzKrJVZ3zg
990 gy3WwNT6kZo6c0tszYqbtvchm
991 gQC8CzKojM/W16i6MG/eafGU3
992 siaOdS0yOI6BgPsw+YZdzlYMa
993 IJGf4M4dyoKIhzdZyQ2bYQrjy
994 Q4LB0lC7aOnsMyYKHHYeRvPxj
995 IQXmdqgOJGq+vsevG06zW+1xg
996 YJh9rCIfnm1GX/KMgxLPG2vXT
997 D/RnLX+D3T3UL7HJYHJhAZD5L
998 59VvjSPsZJHeDCUyWYrvPZesZ
999 DIRvhDD52SKvbheeTJUm6Ehkz
1000 ytNN2SN96QRk8j/iI8ib";
1006 dnssec-validation yes;
1009 <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
1010 <h3 class="title">Note</h3>
1011 None of the keys listed in this example are valid. In particular,
1012 the root key is not valid.
1015 When DNSSEC validation is enabled and properly configured,
1016 the resolver will reject any answers from signed, secure zones
1017 which fail to validate, and will return SERVFAIL to the client.
1020 Responses may fail to validate for any of several reasons,
1021 including missing, expired, or invalid signatures, a key which
1022 does not match the DS RRset in the parent zone, or an insecure
1023 response from a zone which, according to its parent, should have
1026 <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
1027 <h3 class="title">Note</h3>
1029 When the validator receives a response from an unsigned zone
1030 that has a signed parent, it must confirm with the parent
1031 that the zone was intentionally left unsigned. It does
1032 this by verifying, via signed and validated NSEC/NSEC3 records,
1033 that the parent zone contains no DS records for the child.
1036 If the validator <span class="emphasis"><em>can</em></span> prove that the zone
1037 is insecure, then the response is accepted. However, if it
1038 cannot, then it must assume an insecure response to be a
1039 forgery; it rejects the response and logs an error.
1042 The logged error reads "insecurity proof failed" and
1043 "got insecure response; parent indicates it should be secure".
1044 (Prior to BIND 9.7, the logged error was "not insecure".
1045 This referred to the zone, not the response.)
1050 <div class="sect1" lang="en">
1051 <div class="titlepage"><div><div><h2 class="title" style="clear: both">
1052 <a name="dnssec.dynamic.zones"></a>DNSSEC, Dynamic Zones, and Automatic Signing</h2></div></div></div>
1053 <p>As of BIND 9.7.0 it is possible to change a dynamic zone
1054 from insecure to signed and back again. A secure zone can use
1055 either NSEC or NSEC3 chains.</p>
1056 <div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title">
1057 <a name="id2563485"></a>Converting from insecure to secure</h3></div></div></div></div>
1058 <p>Changing a zone from insecure to secure can be done in two
1059 ways: using a dynamic DNS update, or the
1060 <span><strong class="command">auto-dnssec</strong></span> zone option.</p>
1061 <p>For either method, you need to configure
1062 <span><strong class="command">named</strong></span> so that it can see the
1063 <code class="filename">K*</code> files which contain the public and private
1064 parts of the keys that will be used to sign the zone. These files
1065 will have been generated by
1066 <span><strong class="command">dnssec-keygen</strong></span>. You can do this by placing them
1067 in the key-directory, as specified in
1068 <code class="filename">named.conf</code>:</p>
1069 <pre class="programlisting">
1072 update-policy local;
1073 file "dynamic/example.net/example.net";
1074 key-directory "dynamic/example.net";
1077 <p>If one KSK and one ZSK DNSKEY key have been generated, this
1078 configuration will cause all records in the zone to be signed
1079 with the ZSK, and the DNSKEY RRset to be signed with the KSK as
1080 well. An NSEC chain will be generated as part of the initial
1081 signing process.</p>
1082 <div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title">
1083 <a name="id2563523"></a>Dynamic DNS update method</h3></div></div></div></div>
1084 <p>To insert the keys via dynamic update:</p>
1085 <pre class="screen">
1088 > update add example.net DNSKEY 256 3 7 AwEAAZn17pUF0KpbPA2c7Gz76Vb18v0teKT3EyAGfBfL8eQ8al35zz3Y I1m/SAQBxIqMfLtIwqWPdgthsu36azGQAX8=
1089 > update add example.net DNSKEY 257 3 7 AwEAAd/7odU/64o2LGsifbLtQmtO8dFDtTAZXSX2+X3e/UNlq9IHq3Y0 XtC0Iuawl/qkaKVxXe2lo8Ct+dM6UehyCqk=
1092 <p>While the update request will complete almost immediately,
1093 the zone will not be completely signed until
1094 <span><strong class="command">named</strong></span> has had time to walk the zone and
1095 generate the NSEC and RRSIG records. The NSEC record at the apex
1096 will be added last, to signal that there is a complete NSEC
1098 <p>If you wish to sign using NSEC3 instead of NSEC, you should
1099 add an NSEC3PARAM record to the initial update request. If you
1100 wish the NSEC3 chain to have the OPTOUT bit set, set it in the
1101 flags field of the NSEC3PARAM record.</p>
1102 <pre class="screen">
1105 > update add example.net DNSKEY 256 3 7 AwEAAZn17pUF0KpbPA2c7Gz76Vb18v0teKT3EyAGfBfL8eQ8al35zz3Y I1m/SAQBxIqMfLtIwqWPdgthsu36azGQAX8=
1106 > update add example.net DNSKEY 257 3 7 AwEAAd/7odU/64o2LGsifbLtQmtO8dFDtTAZXSX2+X3e/UNlq9IHq3Y0 XtC0Iuawl/qkaKVxXe2lo8Ct+dM6UehyCqk=
1107 > update add example.net NSEC3PARAM 1 1 100 1234567890
1110 <p>Again, this update request will complete almost
1111 immediately; however, the record won't show up until
1112 <span><strong class="command">named</strong></span> has had a chance to build/remove the
1113 relevant chain. A private type record will be created to record
1114 the state of the operation (see below for more details), and will
1115 be removed once the operation completes.</p>
1116 <p>While the initial signing and NSEC/NSEC3 chain generation
1117 is happening, other updates are possible as well.</p>
1118 <div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title">
1119 <a name="id2563627"></a>Fully automatic zone signing</h3></div></div></div></div>
1120 <p>To enable automatic signing, add the
1121 <span><strong class="command">auto-dnssec</strong></span> option to the zone statement in
1122 <code class="filename">named.conf</code>.
1123 <span><strong class="command">auto-dnssec</strong></span> has two possible arguments:
1124 <code class="constant">allow</code> or
1125 <code class="constant">maintain</code>.</p>
1127 <span><strong class="command">auto-dnssec allow</strong></span>,
1128 <span><strong class="command">named</strong></span> can search the key directory for keys
1129 matching the zone, insert them into the zone, and use them to
1130 sign the zone. It will do so only when it receives an
1131 <span><strong class="command">rndc sign <zonename></strong></span> or
1132 <span><strong class="command">rndc loadkeys <zonename></strong></span> command.</p>
1135 <span><strong class="command">auto-dnssec maintain</strong></span> includes the above
1136 functionality, but will also automatically adjust the zone's
1137 DNSKEY records on schedule according to the keys' timing metadata.
1138 (See <a href="man.dnssec-keygen.html" title="dnssec-keygen"><span class="refentrytitle"><span class="application">dnssec-keygen</span></span>(8)</a> and
1139 <a href="man.dnssec-settime.html" title="dnssec-settime"><span class="refentrytitle"><span class="application">dnssec-settime</span></span>(8)</a> for more information.)
1140 If keys are present in the key directory the first time the zone
1141 is loaded, it will be signed immediately, without waiting for an
1142 <span><strong class="command">rndc sign</strong></span> or <span><strong class="command">rndc loadkeys</strong></span>
1143 command. (Those commands can still be used when there are unscheduled
1144 key changes, however.)
1147 <span><strong class="command">auto-dnssec</strong></span> option requires the zone to be
1148 configured to allow dynamic updates, by adding an
1149 <span><strong class="command">allow-update</strong></span> or
1150 <span><strong class="command">update-policy</strong></span> statement to the zone
1151 configuration. If this has not been done, the configuration will
1153 <div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title">
1154 <a name="id2563709"></a>Private-type records</h3></div></div></div></div>
1155 <p>The state of the signing process is signaled by
1156 private-type records (with a default type value of 65534). When
1157 signing is complete, these records will have a nonzero value for
1158 the final octet (for those records which have a nonzero initial
1160 <p>The private type record format: If the first octet is
1161 non-zero then the record indicates that the zone needs to be
1162 signed with the key matching the record, or that all signatures
1163 that match the record should be removed.</p>
1166 <div class="literallayout"><p><br>
1168 algorithm (octet 1)<br>
1169 key id in network order (octet 2 and 3)<br>
1170 removal flag (octet 4)<br>
1171 complete flag (octet 5)<br>
1175 <p>Only records flagged as "complete" can be removed via
1176 dynamic update. Attempts to remove other private type records
1177 will be silently ignored.</p>
1178 <p>If the first octet is zero (this is a reserved algorithm
1179 number that should never appear in a DNSKEY record) then the
1180 record indicates changes to the NSEC3 chains are in progress. The
1181 rest of the record contains an NSEC3PARAM record. The flag field
1182 tells what operation to perform based on the flag bits.</p>
1185 <div class="literallayout"><p><br>
1194 <div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title">
1195 <a name="id2563747"></a>DNSKEY rollovers</h3></div></div></div></div>
1196 <p>As with insecure-to-secure conversions, rolling DNSSEC
1197 keys can be done in two ways: using a dynamic DNS update, or the
1198 <span><strong class="command">auto-dnssec</strong></span> zone option.</p>
1199 <div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title">
1200 <a name="id2563828"></a>Dynamic DNS update method</h3></div></div></div></div>
1201 <p> To perform key rollovers via dynamic update, you need to add
1202 the <code class="filename">K*</code> files for the new keys so that
1203 <span><strong class="command">named</strong></span> can find them. You can then add the new
1204 DNSKEY RRs via dynamic update.
1205 <span><strong class="command">named</strong></span> will then cause the zone to be signed
1206 with the new keys. When the signing is complete the private type
1207 records will be updated so that the last octet is non
1209 <p>If this is for a KSK you need to inform the parent and any
1210 trust anchor repositories of the new KSK.</p>
1211 <p>You should then wait for the maximum TTL in the zone before
1212 removing the old DNSKEY. If it is a KSK that is being updated,
1213 you also need to wait for the DS RRset in the parent to be
1214 updated and its TTL to expire. This ensures that all clients will
1215 be able to verify at least one signature when you remove the old
1217 <p>The old DNSKEY can be removed via UPDATE. Take care to
1218 specify the correct key.
1219 <span><strong class="command">named</strong></span> will clean out any signatures generated
1220 by the old key after the update completes.</p>
1221 <div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title">
1222 <a name="id2563861"></a>Automatic key rollovers</h3></div></div></div></div>
1223 <p>When a new key reaches its activation date (as set by
1224 <span><strong class="command">dnssec-keygen</strong></span> or <span><strong class="command">dnssec-settime</strong></span>),
1225 if the <span><strong class="command">auto-dnssec</strong></span> zone option is set to
1226 <code class="constant">maintain</code>, <span><strong class="command">named</strong></span> will
1227 automatically carry out the key rollover. If the key's algorithm
1228 has not previously been used to sign the zone, then the zone will
1229 be fully signed as quickly as possible. However, if the new key
1230 is replacing an existing key of the same algorithm, then the
1231 zone will be re-signed incrementally, with signatures from the
1232 old key being replaced with signatures from the new key as their
1233 signature validity periods expire. By default, this rollover
1234 completes in 30 days, after which it will be safe to remove the
1235 old key from the DNSKEY RRset.</p>
1236 <div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title">
1237 <a name="id2563888"></a>NSEC3PARAM rollovers via UPDATE</h3></div></div></div></div>
1238 <p>Add the new NSEC3PARAM record via dynamic update. When the
1239 new NSEC3 chain has been generated, the NSEC3PARAM flag field
1240 will be zero. At this point you can remove the old NSEC3PARAM
1241 record. The old chain will be removed after the update request
1243 <div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title">
1244 <a name="id2571816"></a>Converting from NSEC to NSEC3</h3></div></div></div></div>
1245 <p>To do this, you just need to add an NSEC3PARAM record. When
1246 the conversion is complete, the NSEC chain will have been removed
1247 and the NSEC3PARAM record will have a zero flag field. The NSEC3
1248 chain will be generated before the NSEC chain is
1250 <div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title">
1251 <a name="id2571826"></a>Converting from NSEC3 to NSEC</h3></div></div></div></div>
1252 <p>To do this, use <span><strong class="command">nsupdate</strong></span> to
1253 remove all NSEC3PARAM records with a zero flag
1254 field. The NSEC chain will be generated before the NSEC3 chain is
1256 <div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title">
1257 <a name="id2571838"></a>Converting from secure to insecure</h3></div></div></div></div>
1258 <p>To convert a signed zone to unsigned using dynamic DNS,
1259 delete all the DNSKEY records from the zone apex using
1260 <span><strong class="command">nsupdate</strong></span>. All signatures, NSEC or NSEC3 chains,
1261 and associated NSEC3PARAM records will be removed automatically.
1262 This will take place after the update request completes.</p>
1263 <p> This requires the
1264 <span><strong class="command">dnssec-secure-to-insecure</strong></span> option to be set to
1265 <strong class="userinput"><code>yes</code></strong> in
1266 <code class="filename">named.conf</code>.</p>
1267 <p>In addition, if the <span><strong class="command">auto-dnssec maintain</strong></span>
1268 zone statement is used, it should be removed or changed to
1269 <span><strong class="command">allow</strong></span> instead (or it will re-sign).
1271 <div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title">
1272 <a name="id2571876"></a>Periodic re-signing</h3></div></div></div></div>
1273 <p>In any secure zone which supports dynamic updates, named
1274 will periodically re-sign RRsets which have not been re-signed as
1275 a result of some update action. The signature lifetimes will be
1276 adjusted so as to spread the re-sign load over time rather than
1278 <div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title">
1279 <a name="id2572022"></a>NSEC3 and OPTOUT</h3></div></div></div></div>
1281 <span><strong class="command">named</strong></span> only supports creating new NSEC3 chains
1282 where all the NSEC3 records in the zone have the same OPTOUT
1284 <span><strong class="command">named</strong></span> supports UPDATES to zones where the NSEC3
1285 records in the chain have mixed OPTOUT state.
1286 <span><strong class="command">named</strong></span> does not support changing the OPTOUT
1287 state of an individual NSEC3 record, the entire chain needs to be
1288 changed if the OPTOUT state of an individual NSEC3 needs to be
1291 <div class="sect1" lang="en">
1292 <div class="titlepage"><div><div><h2 class="title" style="clear: both">
1293 <a name="rfc5011.support"></a>Dynamic Trust Anchor Management</h2></div></div></div>
1294 <p>BIND 9.7.0 introduces support for RFC 5011, dynamic trust
1295 anchor management. Using this feature allows
1296 <span><strong class="command">named</strong></span> to keep track of changes to critical
1297 DNSSEC keys without any need for the operator to make changes to
1298 configuration files.</p>
1299 <div class="sect2" lang="en">
1300 <div class="titlepage"><div><div><h3 class="title">
1301 <a name="id2572075"></a>Validating Resolver</h3></div></div></div>
1302 <p>To configure a validating resolver to use RFC 5011 to
1303 maintain a trust anchor, configure the trust anchor using a
1304 <span><strong class="command">managed-keys</strong></span> statement. Information about
1305 this can be found in
1306 <a href="Bv9ARM.ch06.html#managed-keys" title="managed-keys Statement Definition
1307 and Usage">the section called “<span><strong class="command">managed-keys</strong></span> Statement Definition
1308 and Usage”</a>.</p>
1310 <div class="sect2" lang="en">
1311 <div class="titlepage"><div><div><h3 class="title">
1312 <a name="id2605958"></a>Authoritative Server</h3></div></div></div>
1313 <p>To set up an authoritative zone for RFC 5011 trust anchor
1314 maintenance, generate two (or more) key signing keys (KSKs) for
1315 the zone. Sign the zone with one of them; this is the "active"
1316 KSK. All KSK's which do not sign the zone are "stand-by"
1318 <p>Any validating resolver which is configured to use the
1319 active KSK as an RFC 5011-managed trust anchor will take note
1320 of the stand-by KSKs in the zone's DNSKEY RRset, and store them
1321 for future reference. The resolver will recheck the zone
1322 periodically, and after 30 days, if the new key is still there,
1323 then the key will be accepted by the resolver as a valid trust
1324 anchor for the zone. Any time after this 30-day acceptance
1325 timer has completed, the active KSK can be revoked, and the
1326 zone can be "rolled over" to the newly accepted key.</p>
1327 <p>The easiest way to place a stand-by key in a zone is to
1328 use the "smart signing" features of
1329 <span><strong class="command">dnssec-keygen</strong></span> and
1330 <span><strong class="command">dnssec-signzone</strong></span>. If a key with a publication
1331 date in the past, but an activation date which is unset or in
1333 <span><strong class="command">dnssec-signzone -S</strong></span>" will include the DNSKEY
1334 record in the zone, but will not sign with it:</p>
1335 <pre class="screen">
1336 $ <strong class="userinput"><code>dnssec-keygen -K keys -f KSK -P now -A now+2y example.net</code></strong>
1337 $ <strong class="userinput"><code>dnssec-signzone -S -K keys example.net</code></strong>
1339 <p>To revoke a key, the new command
1340 <span><strong class="command">dnssec-revoke</strong></span> has been added. This adds the
1341 REVOKED bit to the key flags and re-generates the
1342 <code class="filename">K*.key</code> and
1343 <code class="filename">K*.private</code> files.</p>
1344 <p>After revoking the active key, the zone must be signed
1345 with both the revoked KSK and the new active KSK. (Smart
1346 signing takes care of this automatically.)</p>
1347 <p>Once a key has been revoked and used to sign the DNSKEY
1348 RRset in which it appears, that key will never again be
1349 accepted as a valid trust anchor by the resolver. However,
1350 validation can proceed using the new active key (which had been
1351 accepted by the resolver when it was a stand-by key).</p>
1352 <p>See RFC 5011 for more details on key rollover
1354 <p>When a key has been revoked, its key ID changes,
1355 increasing by 128, and wrapping around at 65535. So, for
1356 example, the key "<code class="filename">Kexample.com.+005+10000</code>" becomes
1357 "<code class="filename">Kexample.com.+005+10128</code>".</p>
1358 <p>If two keys have ID's exactly 128 apart, and one is
1359 revoked, then the two key ID's will collide, causing several
1360 problems. To prevent this,
1361 <span><strong class="command">dnssec-keygen</strong></span> will not generate a new key if
1362 another key is present which may collide. This checking will
1363 only occur if the new keys are written to the same directory
1364 which holds all other keys in use for that zone.</p>
1365 <p>Older versions of BIND 9 did not have this precaution.
1366 Exercise caution if using key revocation on keys that were
1367 generated by previous releases, or if using keys stored in
1368 multiple directories or on multiple machines.</p>
1369 <p>It is expected that a future release of BIND 9 will
1370 address this problem in a different way, by storing revoked
1371 keys with their original unrevoked key ID's.</p>
1374 <div class="sect1" lang="en">
1375 <div class="titlepage"><div><div><h2 class="title" style="clear: both">
1376 <a name="pkcs11"></a>PKCS #11 (Cryptoki) support</h2></div></div></div>
1377 <p>PKCS #11 (Public Key Cryptography Standard #11) defines a
1378 platform- independent API for the control of hardware security
1379 modules (HSMs) and other cryptographic support devices.</p>
1380 <p>BIND 9 is known to work with two HSMs: The Sun SCA 6000
1381 cryptographic acceleration board, tested under Solaris x86, and
1382 the AEP Keyper network-attached key storage device, tested with
1383 Debian Linux, Solaris x86 and Windows Server 2003.</p>
1384 <div class="sect2" lang="en">
1385 <div class="titlepage"><div><div><h3 class="title">
1386 <a name="id2608598"></a>Prerequisites</h3></div></div></div>
1387 <p>See the HSM vendor documentation for information about
1388 installing, initializing, testing and troubleshooting the
1390 <p>BIND 9 uses OpenSSL for cryptography, but stock OpenSSL
1391 does not yet fully support PKCS #11. However, a PKCS #11 engine
1392 for OpenSSL is available from the OpenSolaris project. It has
1393 been modified by ISC to work with with BIND 9, and to provide
1394 new features such as PIN management and key by
1396 <p>The patched OpenSSL depends on a "PKCS #11 provider".
1397 This is a shared library object, providing a low-level PKCS #11
1398 interface to the HSM hardware. It is dynamically loaded by
1399 OpenSSL at runtime. The PKCS #11 provider comes from the HSM
1400 vendor, and and is specific to the HSM to be controlled.</p>
1401 <p>There are two "flavors" of PKCS #11 support provided by
1402 the patched OpenSSL, one of which must be chosen at
1403 configuration time. The correct choice depends on the HSM
1405 <div class="itemizedlist"><ul type="disc">
1406 <li><p>Use 'crypto-accelerator' with HSMs that have hardware
1407 cryptographic acceleration features, such as the SCA 6000
1408 board. This causes OpenSSL to run all supported
1409 cryptographic operations in the HSM.</p></li>
1410 <li><p>Use 'sign-only' with HSMs that are designed to
1411 function primarily as secure key storage devices, but lack
1412 hardware acceleration. These devices are highly secure, but
1413 are not necessarily any faster at cryptography than the
1414 system CPU — often, they are slower. It is therefore
1415 most efficient to use them only for those cryptographic
1416 functions that require access to the secured private key,
1417 such as zone signing, and to use the system CPU for all
1418 other computationally-intensive operations. The AEP Keyper
1419 is an example of such a device.</p></li>
1421 <p>The modified OpenSSL code is included in the BIND 9.7.0
1422 release, in the form of a context diff against the latest OpenSSL.
1424 <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
1425 <h3 class="title">Note</h3>
1426 The latest OpenSSL version at the time of the BIND release
1428 ISC will provide an updated patch as new versions of OpenSSL
1429 are released. The version number in the following examples
1430 is expected to change.</div>
1432 Before building BIND 9 with PKCS #11 support, it will be
1433 necessary to build OpenSSL with this patch in place and inform
1434 it of the path to the HSM-specific PKCS #11 provider
1436 <p>Obtain OpenSSL 0.9.8l:</p>
1437 <pre class="screen">
1438 $ <strong class="userinput"><code>wget <a href="" target="_top">http://www.openssl.org/source/openssl-0.9.8l.tar.gz</a></code></strong>
1440 <p>Extract the tarball:</p>
1441 <pre class="screen">
1442 $ <strong class="userinput"><code>tar zxf openssl-0.9.8l.tar.gz</code></strong>
1444 <p>Apply the patch from the BIND 9 release:</p>
1445 <pre class="screen">
1446 $ <strong class="userinput"><code>patch -p1 -d openssl-0.9.8l \
1447 < bind-9.7.0/bin/pkcs11/openssl-0.9.8l-patch</code></strong>
1449 <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
1450 <h3 class="title">Note</h3>(Note that the patch file may not be compatible with the
1451 "patch" utility on all operating systems. You may need to
1452 install GNU patch.)</div>
1453 <p>When building OpenSSL, place it in a non-standard
1454 location so that it does not interfere with OpenSSL libraries
1455 elsewhere on the system. In the following examples, we choose
1456 to install into "/opt/pkcs11/usr". We will use this location
1457 when we configure BIND 9.</p>
1458 <div class="sect3" lang="en">
1459 <div class="titlepage"><div><div><h4 class="title">
1460 <a name="id2606646"></a>Building OpenSSL for the AEP Keyper on Linux</h4></div></div></div>
1461 <p>The AEP Keyper is a highly secure key storage device,
1462 but does not provide hardware cryptographic acceleration. It
1463 can carry out cryptographic operations, but it is probably
1464 slower than your system's CPU. Therefore, we choose the
1465 'sign-only' flavor when building OpenSSL.</p>
1466 <p>The Keyper-specific PKCS #11 provider library is
1467 delivered with the Keyper software. In this example, we place
1468 it /opt/pkcs11/usr/lib:</p>
1469 <pre class="screen">
1470 $ <strong class="userinput"><code>cp pkcs11.GCC4.0.2.so.4.05 /opt/pkcs11/usr/lib/libpkcs11.so</code></strong>
1472 <p>This library is only available for Linux as a 32-bit
1473 binary. If we are compiling on a 64-bit Linux system, it is
1474 necessary to force a 32-bit build, by specifying -m32 in the
1476 <p>Finally, the Keyper library requires threads, so we
1477 must specify -pthread.</p>
1478 <pre class="screen">
1479 $ <strong class="userinput"><code>cd openssl-0.9.8l</code></strong>
1480 $ <strong class="userinput"><code>./Configure linux-generic32 -m32 -pthread \
1481 --pk11-libname=/opt/pkcs11/usr/lib/libpkcs11.so \
1482 --pk11-flavor=sign-only \
1483 --prefix=/opt/pkcs11/usr</code></strong>
1485 <p>After configuring, run "<span><strong class="command">make</strong></span>"
1486 and "<span><strong class="command">make test</strong></span>". If "<span><strong class="command">make
1487 test</strong></span>" fails with "pthread_atfork() not found", you forgot to
1488 add the -pthread above.</p>
1490 <div class="sect3" lang="en">
1491 <div class="titlepage"><div><div><h4 class="title">
1492 <a name="id2606784"></a>Building OpenSSL for the SCA 6000 on Solaris</h4></div></div></div>
1493 <p>The SCA-6000 PKCS #11 provider is installed as a system
1494 library, libpkcs11. It is a true crypto accelerator, up to 4
1495 times faster than any CPU, so the flavor shall be
1496 'crypto-accelerator'.</p>
1497 <p>In this example, we are building on Solaris x86 on an
1499 <pre class="screen">
1500 $ <strong class="userinput"><code>cd openssl-0.9.8l</code></strong>
1501 $ <strong class="userinput"><code>./Configure solaris64-x86_64-cc \
1502 --pk11-libname=/usr/lib/64/libpkcs11.so \
1503 --pk11-flavor=crypto-accelerator \
1504 --prefix=/opt/pkcs11/usr</code></strong>
1506 <p>(For a 32-bit build, use "solaris-x86-cc" and
1507 /usr/lib/libpkcs11.so.)</p>
1508 <p>After configuring, run
1509 <span><strong class="command">make</strong></span> and
1510 <span><strong class="command">make test</strong></span>.</p>
1511 <p>Once you have built OpenSSL, run
1512 "<span><strong class="command">apps/openssl engine pkcs11</strong></span>" to confirm
1513 that PKCS #11 support was compiled in correctly. The output
1514 should be one of the following lines, depending on the flavor
1516 <pre class="screen">
1517 (pkcs11) PKCS #11 engine support (sign only)
1520 <pre class="screen">
1521 (pkcs11) PKCS #11 engine support (crypto accelerator)
1524 "<span><strong class="command">apps/openssl engine pkcs11 -t</strong></span>". This will
1525 attempt to initialize the PKCS #11 engine. If it is able to
1526 do so successfully, it will report
1527 “<span class="quote"><code class="literal">[ available ]</code></span>”.</p>
1528 <p>If the output is correct, run
1529 "<span><strong class="command">make install</strong></span>" which will install the
1530 modified OpenSSL suite to
1531 <code class="filename">/opt/pkcs11/usr</code>.</p>
1534 <div class="sect2" lang="en">
1535 <div class="titlepage"><div><div><h3 class="title">
1536 <a name="id2607026"></a>Building BIND 9 with PKCS#11</h3></div></div></div>
1537 <p>When building BIND 9, the location of the custom-built
1538 OpenSSL library must be specified via configure.</p>
1539 <div class="sect3" lang="en">
1540 <div class="titlepage"><div><div><h4 class="title">
1541 <a name="id2607034"></a>Configuring BIND 9 for Linux</h4></div></div></div>
1542 <p>To link with the PKCS #11 provider, threads must be
1543 enabled in the BIND 9 build.</p>
1544 <p>The PKCS #11 library for the AEP Keyper is currently
1545 only available as a 32-bit binary. If we are building on a
1546 64-bit host, we must force a 32-bit build by adding "-m32" to
1547 the CC options on the "configure" command line.</p>
1548 <pre class="screen">
1549 $ <strong class="userinput"><code>cd ../bind-9.7.0</code></strong>
1550 $ <strong class="userinput"><code>./configure CC="gcc -m32" --enable-threads \
1551 --with-openssl=/opt/pkcs11/usr \
1552 --with-pkcs11=/opt/pkcs11/usr/lib/libpkcs11.so</code></strong>
1555 <div class="sect3" lang="en">
1556 <div class="titlepage"><div><div><h4 class="title">
1557 <a name="id2607065"></a>Configuring BIND 9 for Solaris</h4></div></div></div>
1558 <p>To link with the PKCS #11 provider, threads must be
1559 enabled in the BIND 9 build.</p>
1560 <pre class="screen">
1561 $ <strong class="userinput"><code>cd ../bind-9.7.0</code></strong>
1562 $ <strong class="userinput"><code>./configure CC="cc -xarch=amd64" --enable-threads \
1563 --with-openssl=/opt/pkcs11/usr \
1564 --with-pkcs11=/usr/lib/64/libpkcs11.so</code></strong>
1566 <p>(For a 32-bit build, omit CC="cc -xarch=amd64".)</p>
1567 <p>If configure complains about OpenSSL not working, you
1568 may have a 32/64-bit architecture mismatch. Or, you may have
1569 incorrectly specified the path to OpenSSL (it should be the
1570 same as the --prefix argument to the OpenSSL
1573 <p>After configuring, run
1574 "<span><strong class="command">make</strong></span>",
1575 "<span><strong class="command">make test</strong></span>" and
1576 "<span><strong class="command">make install</strong></span>".</p>
1578 <div class="sect2" lang="en">
1579 <div class="titlepage"><div><div><h3 class="title">
1580 <a name="id2607121"></a>PKCS #11 Tools</h3></div></div></div>
1581 <p>BIND 9 includes a minimal set of tools to operate the
1583 <span><strong class="command">pkcs11-keygen</strong></span> to generate a new key pair
1585 <span><strong class="command">pkcs11-list</strong></span> to list objects currently
1587 <span><strong class="command">pkcs11-destroy</strong></span> to remove objects.</p>
1588 <p>In UNIX/Linux builds, these tools are built only if BIND
1589 9 is configured with the --with-pkcs11 option. (NOTE: If
1590 --with-pkcs11 is set to "yes", rather than to the path of the
1591 PKCS #11 provider, then the tools will be built but the
1592 provider will be left undefined. Use the -m option or the
1593 PKCS11_PROVIDER environment variable to specify the path to the
1596 <div class="sect2" lang="en">
1597 <div class="titlepage"><div><div><h3 class="title">
1598 <a name="id2607152"></a>Using the HSM</h3></div></div></div>
1599 <p>First, we must set up the runtime environment so the
1600 OpenSSL and PKCS #11 libraries can be loaded:</p>
1601 <pre class="screen">
1602 $ <strong class="userinput"><code>export LD_LIBRARY_PATH=/opt/pkcs11/usr/lib:${LD_LIBRARY_PATH}</code></strong>
1604 <p>When operating an AEP Keyper, it is also necessary to
1605 specify the location of the "machine" file, which stores
1606 information about the Keyper for use by PKCS #11 provider
1607 library. If the machine file is in
1608 <code class="filename">/opt/Keyper/PKCS11Provider/machine</code>,
1610 <pre class="screen">
1611 $ <strong class="userinput"><code>export KEYPER_LIBRARY_PATH=/opt/Keyper/PKCS11Provider</code></strong>
1613 <p>These environment variables must be set whenever running
1614 any tool that uses the HSM, including
1615 <span><strong class="command">pkcs11-keygen</strong></span>,
1616 <span><strong class="command">pkcs11-list</strong></span>,
1617 <span><strong class="command">pkcs11-destroy</strong></span>,
1618 <span><strong class="command">dnssec-keyfromlabel</strong></span>,
1619 <span><strong class="command">dnssec-signzone</strong></span>,
1620 <span><strong class="command">dnssec-keygen</strong></span>(which will use the HSM for
1621 random number generation), and
1622 <span><strong class="command">named</strong></span>.</p>
1623 <p>We can now create and use keys in the HSM. In this case,
1624 we will create a 2048 bit key and give it the label
1626 <pre class="screen">
1627 $ <strong class="userinput"><code>pkcs11-keygen -b 2048 -l sample-ksk</code></strong>
1629 <p>To confirm that the key exists:</p>
1630 <pre class="screen">
1631 $ <strong class="userinput"><code>pkcs11-list</code></strong>
1633 object[0]: handle 2147483658 class 3 label[8] 'sample-ksk' id[0]
1634 object[1]: handle 2147483657 class 2 label[8] 'sample-ksk' id[0]
1636 <p>Before using this key to sign a zone, we must create a
1637 pair of BIND 9 key files. The "dnssec-keyfromlabel" utility
1638 does this. In this case, we will be using the HSM key
1639 "sample-ksk" as the key-signing key for "example.net":</p>
1640 <pre class="screen">
1641 $ <strong class="userinput"><code>dnssec-keyfromlabel -l sample-ksk -f KSK example.net</code></strong>
1643 <p>The resulting K*.key and K*.private files can now be used
1644 to sign the zone. Unlike normal K* files, which contain both
1645 public and private key data, these files will contain only the
1646 public key data, plus an identifier for the private key which
1647 remains stored within the HSM. The HSM handles signing with the
1649 <p>If you wish to generate a second key in the HSM for use
1650 as a zone-signing key, follow the same procedure above, using a
1651 different keylabel, a smaller key size, and omitting "-f KSK"
1652 from the dnssec-keyfromlabel arguments:</p>
1653 <pre class="screen">
1654 $ <strong class="userinput"><code>pkcs11-keygen -b 1024 -l sample-zsk</code></strong>
1655 $ <strong class="userinput"><code>dnssec-keyfromlabel -l sample-zsk example.net</code></strong>
1657 <p>Alternatively, you may prefer to generate a conventional
1658 on-disk key, using dnssec-keygen:</p>
1659 <pre class="screen">
1660 $ <strong class="userinput"><code>dnssec-keygen example.net</code></strong>
1662 <p>This provides less security than an HSM key, but since
1663 HSMs can be slow or cumbersome to use for security reasons, it
1664 may be more efficient to reserve HSM keys for use in the less
1665 frequent key-signing operation. The zone-signing key can be
1666 rolled more frequently, if you wish, to compensate for a
1667 reduction in key security.</p>
1668 <p>Now you can sign the zone. (Note: If not using the -S
1670 <span><strong class="command">dnssec-signzone</strong></span>, it will be necessary to add
1671 the contents of both
1672 <code class="filename">K*.key</code> files to the zone master file before
1674 <pre class="screen">
1675 $ <strong class="userinput"><code>dnssec-signzone -S example.net</code></strong>
1677 Verifying the zone using the following algorithms:
1679 Zone signing complete:
1680 Algorithm: NSEC3RSASHA1: ZSKs: 1, KSKs: 1 active, 0 revoked, 0 stand-by
1684 <div class="sect2" lang="en">
1685 <div class="titlepage"><div><div><h3 class="title">
1686 <a name="id2608784"></a>Specifying the engine on the command line</h3></div></div></div>
1687 <p>The OpenSSL engine can be specified in
1688 <span><strong class="command">named</strong></span> and all of the BIND
1689 <span><strong class="command">dnssec-*</strong></span> tools by using the "-E
1690 <engine>" command line option. If BIND 9 is built with
1691 the --with-pkcs11 option, this option defaults to "pkcs11".
1692 Specifying the engine will generally not be necessary unless
1693 for some reason you wish to use a different OpenSSL
1695 <p>If you wish to disable use of the "pkcs11" engine —
1696 for troubleshooting purposes, or because the HSM is unavailable
1697 — set the engine to the empty string. For example:</p>
1698 <pre class="screen">
1699 $ <strong class="userinput"><code>dnssec-signzone -E '' -S example.net</code></strong>
1702 <span><strong class="command">dnssec-signzone</strong></span> to run as if it were compiled
1703 without the --with-pkcs11 option.</p>
1705 <div class="sect2" lang="en">
1706 <div class="titlepage"><div><div><h3 class="title">
1707 <a name="id2609239"></a>Running named with automatic zone re-signing</h3></div></div></div>
1709 <span><strong class="command">named</strong></span> to dynamically re-sign zones using HSM
1710 keys, and/or to to sign new records inserted via nsupdate, then
1711 named must have access to the HSM PIN. This can be accomplished
1712 by placing the PIN into the openssl.cnf file (in the above
1714 <code class="filename">/opt/pkcs11/usr/ssl/openssl.cnf</code>).</p>
1715 <p>The location of the openssl.cnf file can be overridden by
1716 setting the OPENSSL_CONF environment variable before running
1718 <p>Sample openssl.cnf:</p>
1719 <pre class="programlisting">
1720 openssl_conf = openssl_def
1722 engines = engine_section
1724 pkcs11 = pkcs11_section
1726 PIN = <em class="replaceable"><code><PLACE PIN HERE></code></em>
1728 <p>This will also allow the dnssec-* tools to access the HSM
1729 without PIN entry. (The pkcs11-* tools access the HSM directly,
1730 not via OpenSSL, so a PIN will still be required to use
1732 <div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;">
1733 <h3 class="title">Warning</h3>
1734 <p>Placing the HSM's PIN in a text file in
1735 this manner may reduce the security advantage of using an
1736 HSM. Be sure this is what you want to do before configuring
1737 OpenSSL in this way.</p>
1741 <div class="sect1" lang="en">
1742 <div class="titlepage"><div><div><h2 class="title" style="clear: both">
1743 <a name="id2572468"></a>IPv6 Support in <acronym class="acronym">BIND</acronym> 9</h2></div></div></div>
1745 <acronym class="acronym">BIND</acronym> 9 fully supports all currently
1746 defined forms of IPv6 name to address and address to name
1747 lookups. It will also use IPv6 addresses to make queries when
1748 running on an IPv6 capable system.
1751 For forward lookups, <acronym class="acronym">BIND</acronym> 9 supports
1752 only AAAA records. RFC 3363 deprecated the use of A6 records,
1753 and client-side support for A6 records was accordingly removed
1754 from <acronym class="acronym">BIND</acronym> 9.
1755 However, authoritative <acronym class="acronym">BIND</acronym> 9 name servers still
1756 load zone files containing A6 records correctly, answer queries
1757 for A6 records, and accept zone transfer for a zone containing A6
1761 For IPv6 reverse lookups, <acronym class="acronym">BIND</acronym> 9 supports
1762 the traditional "nibble" format used in the
1763 <span class="emphasis"><em>ip6.arpa</em></span> domain, as well as the older, deprecated
1764 <span class="emphasis"><em>ip6.int</em></span> domain.
1765 Older versions of <acronym class="acronym">BIND</acronym> 9
1766 supported the "binary label" (also known as "bitstring") format,
1767 but support of binary labels has been completely removed per
1769 Many applications in <acronym class="acronym">BIND</acronym> 9 do not understand
1770 the binary label format at all any more, and will return an
1772 In particular, an authoritative <acronym class="acronym">BIND</acronym> 9
1773 name server will not load a zone file containing binary labels.
1776 For an overview of the format and structure of IPv6 addresses,
1777 see <a href="Bv9ARM.ch09.html#ipv6addresses" title="IPv6 addresses (AAAA)">the section called “IPv6 addresses (AAAA)”</a>.
1779 <div class="sect2" lang="en">
1780 <div class="titlepage"><div><div><h3 class="title">
1781 <a name="id2572734"></a>Address Lookups Using AAAA Records</h3></div></div></div>
1783 The IPv6 AAAA record is a parallel to the IPv4 A record,
1784 and, unlike the deprecated A6 record, specifies the entire
1785 IPv6 address in a single record. For example,
1787 <pre class="programlisting">
1788 $ORIGIN example.com.
1789 host 3600 IN AAAA 2001:db8::1
1792 Use of IPv4-in-IPv6 mapped addresses is not recommended.
1793 If a host has an IPv4 address, use an A record, not
1794 a AAAA, with <code class="literal">::ffff:192.168.42.1</code> as
1798 <div class="sect2" lang="en">
1799 <div class="titlepage"><div><div><h3 class="title">
1800 <a name="id2572756"></a>Address to Name Lookups Using Nibble Format</h3></div></div></div>
1802 When looking up an address in nibble format, the address
1803 components are simply reversed, just as in IPv4, and
1804 <code class="literal">ip6.arpa.</code> is appended to the
1806 For example, the following would provide reverse name lookup for
1808 <code class="literal">2001:db8::1</code>.
1810 <pre class="programlisting">
1811 $ORIGIN 0.0.0.0.0.0.0.0.8.b.d.0.1.0.0.2.ip6.arpa.
1812 1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0 14400 IN PTR (
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1831 <td width="40%" align="right" valign="top"> Chapter 5. The <acronym class="acronym">BIND</acronym> 9 Lightweight Resolver</td>