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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#id2564237">Split DNS</a></span></dt>
53 <dd><dl><dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2564256">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#id2570560">Generate Shared Keys for Each Pair of Hosts</a></span></dt>
57 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2570701">Copying the Shared Secret to Both Machines</a></span></dt>
58 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2570712">Informing the Servers of the Key's Existence</a></span></dt>
59 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2570748">Instructing the Server to Use the Key</a></span></dt>
60 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2570806">TSIG Key Based Access Control</a></span></dt>
61 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2570855">Errors</a></span></dt>
63 <dt><span class="sect1"><a href="Bv9ARM.ch04.html#id2570869">TKEY</a></span></dt>
64 <dt><span class="sect1"><a href="Bv9ARM.ch04.html#id2570918">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#id2571054">Generating Keys</a></span></dt>
68 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2571270">Signing the Zone</a></span></dt>
69 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2571351">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#id2610615">Converting from insecure to secure</a></span></dt>
74 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2610652">Dynamic DNS update method</a></span></dt>
75 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2563653">Fully automatic zone signing</a></span></dt>
76 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2563900">Private-type records</a></span></dt>
77 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2563938">DNSKEY rollovers</a></span></dt>
78 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2563950">Dynamic DNS update method</a></span></dt>
79 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2564052">Automatic key rollovers</a></span></dt>
80 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2564078">NSEC3PARAM rollovers via UPDATE</a></span></dt>
81 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2564088">Converting from NSEC to NSEC3</a></span></dt>
82 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2569832">Converting from NSEC3 to NSEC</a></span></dt>
83 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2569845">Converting from secure to insecure</a></span></dt>
84 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2569882">Periodic re-signing</a></span></dt>
85 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2569892">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#id2610129">Validating Resolver</a></span></dt>
90 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2610151">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#id2613326">Prerequisites</a></span></dt>
95 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2611166">Building BIND 9 with PKCS#11</a></span></dt>
96 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2613408">PKCS #11 Tools</a></span></dt>
97 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2613438">Using the HSM</a></span></dt>
98 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2637735">Specifying the engine on the command line</a></span></dt>
99 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2637781">Running named with automatic zone re-signing</a></span></dt>
101 <dt><span class="sect1"><a href="Bv9ARM.ch04.html#id2571571">IPv6 Support in <acronym class="acronym">BIND</acronym> 9</a></span></dt>
103 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2571837">Address Lookups Using AAAA Records</a></span></dt>
104 <dt><span class="sect2"><a href="Bv9ARM.ch04.html#id2571859">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 Dynamic updates using Kerberos signed requests can be made
158 using the TKEY/GSS protocol by setting either the
159 <span><strong class="command">tkey-gssapi-keytab</strong></span> option, or alternatively
160 by setting both the <span><strong class="command">tkey-gssapi-credential</strong></span>
161 and <span><strong class="command">tkey-domain</strong></span> options. Once enabled,
162 Kerberos signed requests will be matched against the update
163 policies for the zone, using the Kerberos principal as the
164 signer for the request.
167 Updating of secure zones (zones using DNSSEC) follows RFC
168 3007: RRSIG, NSEC and NSEC3 records affected by updates are
169 automatically regenerated by the server using an online
170 zone key. Update authorization is based on transaction
171 signatures and an explicit server policy.
173 <div class="sect2" lang="en">
174 <div class="titlepage"><div><div><h3 class="title">
175 <a name="journal"></a>The journal file</h3></div></div></div>
177 All changes made to a zone using dynamic update are stored
178 in the zone's journal file. This file is automatically created
179 by the server when the first dynamic update takes place.
180 The name of the journal file is formed by appending the extension
181 <code class="filename">.jnl</code> to the name of the
183 file unless specifically overridden. The journal file is in a
184 binary format and should not be edited manually.
187 The server will also occasionally write ("dump")
188 the complete contents of the updated zone to its zone file.
189 This is not done immediately after
190 each dynamic update, because that would be too slow when a large
191 zone is updated frequently. Instead, the dump is delayed by
192 up to 15 minutes, allowing additional updates to take place.
193 During the dump process, transient files will be created
194 with the extensions <code class="filename">.jnw</code> and
195 <code class="filename">.jbk</code>; under ordinary circumstances, these
196 will be removed when the dump is complete, and can be safely
200 When a server is restarted after a shutdown or crash, it will replay
201 the journal file to incorporate into the zone any updates that
203 place after the last zone dump.
206 Changes that result from incoming incremental zone transfers are
208 journalled in a similar way.
211 The zone files of dynamic zones cannot normally be edited by
212 hand because they are not guaranteed to contain the most recent
213 dynamic changes — those are only in the journal file.
214 The only way to ensure that the zone file of a dynamic zone
215 is up to date is to run <span><strong class="command">rndc stop</strong></span>.
218 If you have to make changes to a dynamic zone
219 manually, the following procedure will work:
220 Disable dynamic updates to the zone using
221 <span><strong class="command">rndc freeze <em class="replaceable"><code>zone</code></em></strong></span>.
222 This will update the zone's master file with the changes
223 stored in its <code class="filename">.jnl</code> file.
224 Edit the zone file. Run
225 <span><strong class="command">rndc thaw <em class="replaceable"><code>zone</code></em></strong></span>
226 to reload the changed zone and re-enable dynamic updates.
229 <span><strong class="command">rndc sync <em class="replaceable"><code>zone</code></em></strong></span>
230 will update the zone file with changes from the journal file
231 without stopping dynamic updates; this may be useful for viewing
232 the current zone state. To remove the <code class="filename">.jnl</code>
233 file after updating the zone file, use
234 <span><strong class="command">rndc sync -clean</strong></span>.
238 <div class="sect1" lang="en">
239 <div class="titlepage"><div><div><h2 class="title" style="clear: both">
240 <a name="incremental_zone_transfers"></a>Incremental Zone Transfers (IXFR)</h2></div></div></div>
242 The incremental zone transfer (IXFR) protocol is a way for
243 slave servers to transfer only changed data, instead of having to
244 transfer the entire zone. The IXFR protocol is specified in RFC
245 1995. See <a href="Bv9ARM.ch11.html#proposed_standards">Proposed Standards</a>.
248 When acting as a master, <acronym class="acronym">BIND</acronym> 9
249 supports IXFR for those zones
250 where the necessary change history information is available. These
251 include master zones maintained by dynamic update and slave zones
252 whose data was obtained by IXFR. For manually maintained master
253 zones, and for slave zones obtained by performing a full zone
254 transfer (AXFR), IXFR is supported only if the option
255 <span><strong class="command">ixfr-from-differences</strong></span> is set
256 to <strong class="userinput"><code>yes</code></strong>.
259 When acting as a slave, <acronym class="acronym">BIND</acronym> 9 will
260 attempt to use IXFR unless
261 it is explicitly disabled. For more information about disabling
262 IXFR, see the description of the <span><strong class="command">request-ixfr</strong></span> clause
263 of the <span><strong class="command">server</strong></span> statement.
266 <div class="sect1" lang="en">
267 <div class="titlepage"><div><div><h2 class="title" style="clear: both">
268 <a name="id2564237"></a>Split DNS</h2></div></div></div>
270 Setting up different views, or visibility, of the DNS space to
271 internal and external resolvers is usually referred to as a
272 <span class="emphasis"><em>Split DNS</em></span> setup. There are several
273 reasons an organization would want to set up its DNS this way.
276 One common reason for setting up a DNS system this way is
277 to hide "internal" DNS information from "external" clients on the
278 Internet. There is some debate as to whether or not this is actually
280 Internal DNS information leaks out in many ways (via email headers,
281 for example) and most savvy "attackers" can find the information
282 they need using other means.
283 However, since listing addresses of internal servers that
284 external clients cannot possibly reach can result in
285 connection delays and other annoyances, an organization may
286 choose to use a Split DNS to present a consistent view of itself
287 to the outside world.
290 Another common reason for setting up a Split DNS system is
291 to allow internal networks that are behind filters or in RFC 1918
292 space (reserved IP space, as documented in RFC 1918) to resolve DNS
293 on the Internet. Split DNS can also be used to allow mail from outside
294 back in to the internal network.
296 <div class="sect2" lang="en">
297 <div class="titlepage"><div><div><h3 class="title">
298 <a name="id2564256"></a>Example split DNS setup</h3></div></div></div>
300 Let's say a company named <span class="emphasis"><em>Example, Inc.</em></span>
301 (<code class="literal">example.com</code>)
302 has several corporate sites that have an internal network with
304 Internet Protocol (IP) space and an external demilitarized zone (DMZ),
305 or "outside" section of a network, that is available to the public.
308 <span class="emphasis"><em>Example, Inc.</em></span> wants its internal clients
309 to be able to resolve external hostnames and to exchange mail with
310 people on the outside. The company also wants its internal resolvers
311 to have access to certain internal-only zones that are not available
312 at all outside of the internal network.
315 In order to accomplish this, the company will set up two sets
316 of name servers. One set will be on the inside network (in the
318 IP space) and the other set will be on bastion hosts, which are
320 hosts that can talk to both sides of its network, in the DMZ.
323 The internal servers will be configured to forward all queries,
324 except queries for <code class="filename">site1.internal</code>, <code class="filename">site2.internal</code>, <code class="filename">site1.example.com</code>,
325 and <code class="filename">site2.example.com</code>, to the servers
327 DMZ. These internal servers will have complete sets of information
328 for <code class="filename">site1.example.com</code>, <code class="filename">site2.example.com</code>, <code class="filename">site1.internal</code>,
329 and <code class="filename">site2.internal</code>.
332 To protect the <code class="filename">site1.internal</code> and <code class="filename">site2.internal</code> domains,
333 the internal name servers must be configured to disallow all queries
334 to these domains from any external hosts, including the bastion
338 The external servers, which are on the bastion hosts, will
339 be configured to serve the "public" version of the <code class="filename">site1</code> and <code class="filename">site2.example.com</code> zones.
340 This could include things such as the host records for public servers
341 (<code class="filename">www.example.com</code> and <code class="filename">ftp.example.com</code>),
342 and mail exchange (MX) records (<code class="filename">a.mx.example.com</code> and <code class="filename">b.mx.example.com</code>).
345 In addition, the public <code class="filename">site1</code> and <code class="filename">site2.example.com</code> zones
346 should have special MX records that contain wildcard (`*') records
347 pointing to the bastion hosts. This is needed because external mail
348 servers do not have any other way of looking up how to deliver mail
349 to those internal hosts. With the wildcard records, the mail will
350 be delivered to the bastion host, which can then forward it on to
354 Here's an example of a wildcard MX record:
356 <pre class="programlisting">* IN MX 10 external1.example.com.</pre>
358 Now that they accept mail on behalf of anything in the internal
359 network, the bastion hosts will need to know how to deliver mail
360 to internal hosts. In order for this to work properly, the resolvers
362 the bastion hosts will need to be configured to point to the internal
363 name servers for DNS resolution.
366 Queries for internal hostnames will be answered by the internal
367 servers, and queries for external hostnames will be forwarded back
368 out to the DNS servers on the bastion hosts.
371 In order for all this to work properly, internal clients will
372 need to be configured to query <span class="emphasis"><em>only</em></span> the internal
373 name servers for DNS queries. This could also be enforced via
375 filtering on the network.
378 If everything has been set properly, <span class="emphasis"><em>Example, Inc.</em></span>'s
379 internal clients will now be able to:
381 <div class="itemizedlist"><ul type="disc">
383 Look up any hostnames in the <code class="literal">site1</code>
385 <code class="literal">site2.example.com</code> zones.
388 Look up any hostnames in the <code class="literal">site1.internal</code> and
389 <code class="literal">site2.internal</code> domains.
391 <li>Look up any hostnames on the Internet.</li>
392 <li>Exchange mail with both internal and external people.</li>
395 Hosts on the Internet will be able to:
397 <div class="itemizedlist"><ul type="disc">
399 Look up any hostnames in the <code class="literal">site1</code>
401 <code class="literal">site2.example.com</code> zones.
404 Exchange mail with anyone in the <code class="literal">site1</code> and
405 <code class="literal">site2.example.com</code> zones.
409 Here is an example configuration for the setup we just
410 described above. Note that this is only configuration information;
411 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>.
414 Internal DNS server config:
416 <pre class="programlisting">
418 acl internals { 172.16.72.0/24; 192.168.1.0/24; };
420 acl externals { <code class="varname">bastion-ips-go-here</code>; };
426 // forward to external servers
428 <code class="varname">bastion-ips-go-here</code>;
430 // sample allow-transfer (no one)
431 allow-transfer { none; };
432 // restrict query access
433 allow-query { internals; externals; };
434 // restrict recursion
435 allow-recursion { internals; };
440 // sample master zone
441 zone "site1.example.com" {
443 file "m/site1.example.com";
444 // do normal iterative resolution (do not forward)
446 allow-query { internals; externals; };
447 allow-transfer { internals; };
451 zone "site2.example.com" {
453 file "s/site2.example.com";
454 masters { 172.16.72.3; };
456 allow-query { internals; externals; };
457 allow-transfer { internals; };
460 zone "site1.internal" {
462 file "m/site1.internal";
464 allow-query { internals; };
465 allow-transfer { internals; }
468 zone "site2.internal" {
470 file "s/site2.internal";
471 masters { 172.16.72.3; };
473 allow-query { internals };
474 allow-transfer { internals; }
478 External (bastion host) DNS server config:
480 <pre class="programlisting">
481 acl internals { 172.16.72.0/24; 192.168.1.0/24; };
483 acl externals { bastion-ips-go-here; };
488 // sample allow-transfer (no one)
489 allow-transfer { none; };
490 // default query access
491 allow-query { any; };
492 // restrict cache access
493 allow-query-cache { internals; externals; };
494 // restrict recursion
495 allow-recursion { internals; externals; };
501 zone "site1.example.com" {
503 file "m/site1.foo.com";
504 allow-transfer { internals; externals; };
507 zone "site2.example.com" {
509 file "s/site2.foo.com";
510 masters { another_bastion_host_maybe; };
511 allow-transfer { internals; externals; }
515 In the <code class="filename">resolv.conf</code> (or equivalent) on
518 <pre class="programlisting">
520 nameserver 172.16.72.2
521 nameserver 172.16.72.3
522 nameserver 172.16.72.4
526 <div class="sect1" lang="en">
527 <div class="titlepage"><div><div><h2 class="title" style="clear: both">
528 <a name="tsig"></a>TSIG</h2></div></div></div>
530 This is a short guide to setting up Transaction SIGnatures
531 (TSIG) based transaction security in <acronym class="acronym">BIND</acronym>. It describes changes
532 to the configuration file as well as what changes are required for
533 different features, including the process of creating transaction
534 keys and using transaction signatures with <acronym class="acronym">BIND</acronym>.
537 <acronym class="acronym">BIND</acronym> primarily supports TSIG for server
538 to server communication.
539 This includes zone transfer, notify, and recursive query messages.
540 Resolvers based on newer versions of <acronym class="acronym">BIND</acronym> 8 have limited support
544 TSIG can also be useful for dynamic update. A primary
545 server for a dynamic zone should control access to the dynamic
546 update service, but IP-based access control is insufficient.
547 The cryptographic access control provided by TSIG
548 is far superior. The <span><strong class="command">nsupdate</strong></span>
549 program supports TSIG via the <code class="option">-k</code> and
550 <code class="option">-y</code> command line options or inline by use
551 of the <span><strong class="command">key</strong></span>.
553 <div class="sect2" lang="en">
554 <div class="titlepage"><div><div><h3 class="title">
555 <a name="id2570560"></a>Generate Shared Keys for Each Pair of Hosts</h3></div></div></div>
557 A shared secret is generated to be shared between <span class="emphasis"><em>host1</em></span> and <span class="emphasis"><em>host2</em></span>.
558 An arbitrary key name is chosen: "host1-host2.". The key name must
559 be the same on both hosts.
561 <div class="sect3" lang="en">
562 <div class="titlepage"><div><div><h4 class="title">
563 <a name="id2570577"></a>Automatic Generation</h4></div></div></div>
565 The following command will generate a 128-bit (16 byte) HMAC-SHA256
566 key as described above. Longer keys are better, but shorter keys
567 are easier to read. Note that the maximum key length is the digest
568 length, here 256 bits.
571 <strong class="userinput"><code>dnssec-keygen -a hmac-sha256 -b 128 -n HOST host1-host2.</code></strong>
574 The key is in the file <code class="filename">Khost1-host2.+163+00000.private</code>.
575 Nothing directly uses this file, but the base-64 encoded string
576 following "<code class="literal">Key:</code>"
577 can be extracted from the file and used as a shared secret:
579 <pre class="programlisting">Key: La/E5CjG9O+os1jq0a2jdA==</pre>
581 The string "<code class="literal">La/E5CjG9O+os1jq0a2jdA==</code>" can
582 be used as the shared secret.
585 <div class="sect3" lang="en">
586 <div class="titlepage"><div><div><h4 class="title">
587 <a name="id2570683"></a>Manual Generation</h4></div></div></div>
589 The shared secret is simply a random sequence of bits, encoded
590 in base-64. Most ASCII strings are valid base-64 strings (assuming
591 the length is a multiple of 4 and only valid characters are used),
592 so the shared secret can be manually generated.
595 Also, a known string can be run through <span><strong class="command">mmencode</strong></span> or
596 a similar program to generate base-64 encoded data.
600 <div class="sect2" lang="en">
601 <div class="titlepage"><div><div><h3 class="title">
602 <a name="id2570701"></a>Copying the Shared Secret to Both Machines</h3></div></div></div>
604 This is beyond the scope of DNS. A secure transport mechanism
605 should be used. This could be secure FTP, ssh, telephone, etc.
608 <div class="sect2" lang="en">
609 <div class="titlepage"><div><div><h3 class="title">
610 <a name="id2570712"></a>Informing the Servers of the Key's Existence</h3></div></div></div>
612 Imagine <span class="emphasis"><em>host1</em></span> and <span class="emphasis"><em>host 2</em></span>
614 both servers. The following is added to each server's <code class="filename">named.conf</code> file:
616 <pre class="programlisting">
618 algorithm hmac-sha256;
619 secret "La/E5CjG9O+os1jq0a2jdA==";
623 The secret is the one generated above. Since this is a secret, it
624 is recommended that either <code class="filename">named.conf</code> be
625 non-world readable, or the key directive be added to a non-world
626 readable file that is included by <code class="filename">named.conf</code>.
629 At this point, the key is recognized. This means that if the
630 server receives a message signed by this key, it can verify the
631 signature. If the signature is successfully verified, the
632 response is signed by the same key.
635 <div class="sect2" lang="en">
636 <div class="titlepage"><div><div><h3 class="title">
637 <a name="id2570748"></a>Instructing the Server to Use the Key</h3></div></div></div>
639 Since keys are shared between two hosts only, the server must
640 be told when keys are to be used. The following is added to the <code class="filename">named.conf</code> file
641 for <span class="emphasis"><em>host1</em></span>, if the IP address of <span class="emphasis"><em>host2</em></span> is
644 <pre class="programlisting">
646 keys { host1-host2. ;};
650 Multiple keys may be present, but only the first is used.
651 This directive does not contain any secrets, so it may be in a
656 If <span class="emphasis"><em>host1</em></span> sends a message that is a request
657 to that address, the message will be signed with the specified key. <span class="emphasis"><em>host1</em></span> will
658 expect any responses to signed messages to be signed with the same
662 A similar statement must be present in <span class="emphasis"><em>host2</em></span>'s
663 configuration file (with <span class="emphasis"><em>host1</em></span>'s address) for <span class="emphasis"><em>host2</em></span> to
664 sign request messages to <span class="emphasis"><em>host1</em></span>.
667 <div class="sect2" lang="en">
668 <div class="titlepage"><div><div><h3 class="title">
669 <a name="id2570806"></a>TSIG Key Based Access Control</h3></div></div></div>
671 <acronym class="acronym">BIND</acronym> allows IP addresses and ranges
672 to be specified in ACL
674 <span><strong class="command">allow-{ query | transfer | update }</strong></span>
676 This has been extended to allow TSIG keys also. The above key would
677 be denoted <span><strong class="command">key host1-host2.</strong></span>
680 An example of an <span><strong class="command">allow-update</strong></span> directive would be:
682 <pre class="programlisting">
683 allow-update { key host1-host2. ;};
686 This allows dynamic updates to succeed only if the request
687 was signed by a key named "<span><strong class="command">host1-host2.</strong></span>".
690 See <a href="Bv9ARM.ch06.html#dynamic_update_policies" title="Dynamic Update Policies">the section called “Dynamic Update Policies”</a> for a discussion of
691 the more flexible <span><strong class="command">update-policy</strong></span> statement.
694 <div class="sect2" lang="en">
695 <div class="titlepage"><div><div><h3 class="title">
696 <a name="id2570855"></a>Errors</h3></div></div></div>
698 The processing of TSIG signed messages can result in
699 several errors. If a signed message is sent to a non-TSIG aware
700 server, a FORMERR (format error) will be returned, since the server will not
701 understand the record. This is a result of misconfiguration,
702 since the server must be explicitly configured to send a TSIG
703 signed message to a specific server.
706 If a TSIG aware server receives a message signed by an
707 unknown key, the response will be unsigned with the TSIG
708 extended error code set to BADKEY. If a TSIG aware server
709 receives a message with a signature that does not validate, the
710 response will be unsigned with the TSIG extended error code set
711 to BADSIG. If a TSIG aware server receives a message with a time
712 outside of the allowed range, the response will be signed with
713 the TSIG extended error code set to BADTIME, and the time values
714 will be adjusted so that the response can be successfully
715 verified. In any of these cases, the message's rcode (response code) is set to
716 NOTAUTH (not authenticated).
720 <div class="sect1" lang="en">
721 <div class="titlepage"><div><div><h2 class="title" style="clear: both">
722 <a name="id2570869"></a>TKEY</h2></div></div></div>
723 <p><span><strong class="command">TKEY</strong></span>
724 is a mechanism for automatically generating a shared secret
725 between two hosts. There are several "modes" of
726 <span><strong class="command">TKEY</strong></span> that specify how the key is generated
727 or assigned. <acronym class="acronym">BIND</acronym> 9 implements only one of
728 these modes, the Diffie-Hellman key exchange. Both hosts are
729 required to have a Diffie-Hellman KEY record (although this
730 record is not required to be present in a zone). The
731 <span><strong class="command">TKEY</strong></span> process must use signed messages,
732 signed either by TSIG or SIG(0). The result of
733 <span><strong class="command">TKEY</strong></span> is a shared secret that can be used to
734 sign messages with TSIG. <span><strong class="command">TKEY</strong></span> can also be
735 used to delete shared secrets that it had previously
739 The <span><strong class="command">TKEY</strong></span> process is initiated by a
741 or server by sending a signed <span><strong class="command">TKEY</strong></span>
743 (including any appropriate KEYs) to a TKEY-aware server. The
744 server response, if it indicates success, will contain a
745 <span><strong class="command">TKEY</strong></span> record and any appropriate keys.
747 this exchange, both participants have enough information to
748 determine the shared secret; the exact process depends on the
749 <span><strong class="command">TKEY</strong></span> mode. When using the
751 <span><strong class="command">TKEY</strong></span> mode, Diffie-Hellman keys are
753 and the shared secret is derived by both participants.
756 <div class="sect1" lang="en">
757 <div class="titlepage"><div><div><h2 class="title" style="clear: both">
758 <a name="id2570918"></a>SIG(0)</h2></div></div></div>
760 <acronym class="acronym">BIND</acronym> 9 partially supports DNSSEC SIG(0)
761 transaction signatures as specified in RFC 2535 and RFC 2931.
763 uses public/private keys to authenticate messages. Access control
764 is performed in the same manner as TSIG keys; privileges can be
765 granted or denied based on the key name.
768 When a SIG(0) signed message is received, it will only be
769 verified if the key is known and trusted by the server; the server
770 will not attempt to locate and/or validate the key.
773 SIG(0) signing of multiple-message TCP streams is not
777 The only tool shipped with <acronym class="acronym">BIND</acronym> 9 that
778 generates SIG(0) signed messages is <span><strong class="command">nsupdate</strong></span>.
781 <div class="sect1" lang="en">
782 <div class="titlepage"><div><div><h2 class="title" style="clear: both">
783 <a name="DNSSEC"></a>DNSSEC</h2></div></div></div>
785 Cryptographic authentication of DNS information is possible
786 through the DNS Security (<span class="emphasis"><em>DNSSEC-bis</em></span>) extensions,
787 defined in RFC 4033, RFC 4034, and RFC 4035.
788 This section describes the creation and use of DNSSEC signed zones.
791 In order to set up a DNSSEC secure zone, there are a series
792 of steps which must be followed. <acronym class="acronym">BIND</acronym>
795 that are used in this process, which are explained in more detail
796 below. In all cases, the <code class="option">-h</code> option prints a
797 full list of parameters. Note that the DNSSEC tools require the
798 keyset files to be in the working directory or the
799 directory specified by the <code class="option">-d</code> option, and
800 that the tools shipped with BIND 9.2.x and earlier are not compatible
801 with the current ones.
804 There must also be communication with the administrators of
805 the parent and/or child zone to transmit keys. A zone's security
806 status must be indicated by the parent zone for a DNSSEC capable
807 resolver to trust its data. This is done through the presence
808 or absence of a <code class="literal">DS</code> record at the
813 For other servers to trust data in this zone, they must
814 either be statically configured with this zone's zone key or the
815 zone key of another zone above this one in the DNS tree.
817 <div class="sect2" lang="en">
818 <div class="titlepage"><div><div><h3 class="title">
819 <a name="id2571054"></a>Generating Keys</h3></div></div></div>
821 The <span><strong class="command">dnssec-keygen</strong></span> program is used to
825 A secure zone must contain one or more zone keys. The
826 zone keys will sign all other records in the zone, as well as
827 the zone keys of any secure delegated zones. Zone keys must
828 have the same name as the zone, a name type of
829 <span><strong class="command">ZONE</strong></span>, and must be usable for
831 It is recommended that zone keys use a cryptographic algorithm
832 designated as "mandatory to implement" by the IETF; currently
833 the only one is RSASHA1.
836 The following command will generate a 768-bit RSASHA1 key for
837 the <code class="filename">child.example</code> zone:
840 <strong class="userinput"><code>dnssec-keygen -a RSASHA1 -b 768 -n ZONE child.example.</code></strong>
843 Two output files will be produced:
844 <code class="filename">Kchild.example.+005+12345.key</code> and
845 <code class="filename">Kchild.example.+005+12345.private</code>
847 12345 is an example of a key tag). The key filenames contain
848 the key name (<code class="filename">child.example.</code>),
850 is DSA, 1 is RSAMD5, 5 is RSASHA1, etc.), and the key tag (12345 in
852 The private key (in the <code class="filename">.private</code>
854 used to generate signatures, and the public key (in the
855 <code class="filename">.key</code> file) is used for signature
859 To generate another key with the same properties (but with
860 a different key tag), repeat the above command.
863 The <span><strong class="command">dnssec-keyfromlabel</strong></span> program is used
864 to get a key pair from a crypto hardware and build the key
865 files. Its usage is similar to <span><strong class="command">dnssec-keygen</strong></span>.
868 The public keys should be inserted into the zone file by
869 including the <code class="filename">.key</code> files using
870 <span><strong class="command">$INCLUDE</strong></span> statements.
873 <div class="sect2" lang="en">
874 <div class="titlepage"><div><div><h3 class="title">
875 <a name="id2571270"></a>Signing the Zone</h3></div></div></div>
877 The <span><strong class="command">dnssec-signzone</strong></span> program is used
881 Any <code class="filename">keyset</code> files corresponding to
882 secure subzones should be present. The zone signer will
883 generate <code class="literal">NSEC</code>, <code class="literal">NSEC3</code>
884 and <code class="literal">RRSIG</code> records for the zone, as
885 well as <code class="literal">DS</code> for the child zones if
886 <code class="literal">'-g'</code> is specified. If <code class="literal">'-g'</code>
887 is not specified, then DS RRsets for the secure child
888 zones need to be added manually.
891 The following command signs the zone, assuming it is in a
892 file called <code class="filename">zone.child.example</code>. By
893 default, all zone keys which have an available private key are
894 used to generate signatures.
897 <strong class="userinput"><code>dnssec-signzone -o child.example zone.child.example</code></strong>
900 One output file is produced:
901 <code class="filename">zone.child.example.signed</code>. This
903 should be referenced by <code class="filename">named.conf</code>
905 input file for the zone.
907 <p><span><strong class="command">dnssec-signzone</strong></span>
908 will also produce a keyset and dsset files and optionally a
909 dlvset file. These are used to provide the parent zone
910 administrators with the <code class="literal">DNSKEYs</code> (or their
911 corresponding <code class="literal">DS</code> records) that are the
912 secure entry point to the zone.
915 <div class="sect2" lang="en">
916 <div class="titlepage"><div><div><h3 class="title">
917 <a name="id2571351"></a>Configuring Servers</h3></div></div></div>
919 To enable <span><strong class="command">named</strong></span> to respond appropriately
920 to DNS requests from DNSSEC aware clients,
921 <span><strong class="command">dnssec-enable</strong></span> must be set to yes.
922 (This is the default setting.)
925 To enable <span><strong class="command">named</strong></span> to validate answers from
926 other servers, the <span><strong class="command">dnssec-enable</strong></span> option
927 must be set to <strong class="userinput"><code>yes</code></strong>, and the
928 <span><strong class="command">dnssec-validation</strong></span> options must be set to
929 <strong class="userinput"><code>yes</code></strong> or <strong class="userinput"><code>auto</code></strong>.
932 If <span><strong class="command">dnssec-validation</strong></span> is set to
933 <strong class="userinput"><code>auto</code></strong>, then a default
934 trust anchor for the DNS root zone will be used.
935 If it is set to <strong class="userinput"><code>yes</code></strong>, however,
936 then at least one trust anchor must be configured
937 with a <span><strong class="command">trusted-keys</strong></span> or
938 <span><strong class="command">managed-keys</strong></span> statement in
939 <code class="filename">named.conf</code>, or DNSSEC validation
940 will not occur. The default setting is
941 <strong class="userinput"><code>yes</code></strong>.
944 <span><strong class="command">trusted-keys</strong></span> are copies of DNSKEY RRs
945 for zones that are used to form the first link in the
946 cryptographic chain of trust. All keys listed in
947 <span><strong class="command">trusted-keys</strong></span> (and corresponding zones)
948 are deemed to exist and only the listed keys will be used
949 to validated the DNSKEY RRset that they are from.
952 <span><strong class="command">managed-keys</strong></span> are trusted keys which are
953 automatically kept up to date via RFC 5011 trust anchor
957 <span><strong class="command">trusted-keys</strong></span> and
958 <span><strong class="command">managed-keys</strong></span> are described in more detail
959 later in this document.
962 Unlike <acronym class="acronym">BIND</acronym> 8, <acronym class="acronym">BIND</acronym>
963 9 does not verify signatures on load, so zone keys for
964 authoritative zones do not need to be specified in the
968 After DNSSEC gets established, a typical DNSSEC configuration
969 will look something like the following. It has one or
970 more public keys for the root. This allows answers from
971 outside the organization to be validated. It will also
972 have several keys for parts of the namespace the organization
973 controls. These are here to ensure that <span><strong class="command">named</strong></span>
974 is immune to compromises in the DNSSEC components of the security
977 <pre class="programlisting">
980 "." initial-key 257 3 3 "BNY4wrWM1nCfJ+CXd0rVXyYmobt7sEEfK3clRbGaTwS
981 JxrGkxJWoZu6I7PzJu/E9gx4UC1zGAHlXKdE4zYIpRh
982 aBKnvcC2U9mZhkdUpd1Vso/HAdjNe8LmMlnzY3zy2Xy
983 4klWOADTPzSv9eamj8V18PHGjBLaVtYvk/ln5ZApjYg
984 hf+6fElrmLkdaz MQ2OCnACR817DF4BBa7UR/beDHyp
985 5iWTXWSi6XmoJLbG9Scqc7l70KDqlvXR3M/lUUVRbke
986 g1IPJSidmK3ZyCllh4XSKbje/45SKucHgnwU5jefMtq
987 66gKodQj+MiA21AfUVe7u99WzTLzY3qlxDhxYQQ20FQ
988 97S+LKUTpQcq27R7AT3/V5hRQxScINqwcz4jYqZD2fQ
989 dgxbcDTClU0CRBdiieyLMNzXG3";
993 /* Key for our organization's forward zone */
994 example.com. 257 3 5 "AwEAAaxPMcR2x0HbQV4WeZB6oEDX+r0QM6
995 5KbhTjrW1ZaARmPhEZZe3Y9ifgEuq7vZ/z
996 GZUdEGNWy+JZzus0lUptwgjGwhUS1558Hb
997 4JKUbbOTcM8pwXlj0EiX3oDFVmjHO444gL
998 kBOUKUf/mC7HvfwYH/Be22GnClrinKJp1O
999 g4ywzO9WglMk7jbfW33gUKvirTHr25GL7S
1000 TQUzBb5Usxt8lgnyTUHs1t3JwCY5hKZ6Cq
1001 FxmAVZP20igTixin/1LcrgX/KMEGd/biuv
1002 F4qJCyduieHukuY3H4XMAcR+xia2nIUPvm
1003 /oyWR8BW/hWdzOvnSCThlHf3xiYleDbt/o
1006 /* Key for our reverse zone. */
1007 2.0.192.IN-ADDRPA.NET. 257 3 5 "AQOnS4xn/IgOUpBPJ3bogzwc
1008 xOdNax071L18QqZnQQQAVVr+i
1009 LhGTnNGp3HoWQLUIzKrJVZ3zg
1010 gy3WwNT6kZo6c0tszYqbtvchm
1011 gQC8CzKojM/W16i6MG/eafGU3
1012 siaOdS0yOI6BgPsw+YZdzlYMa
1013 IJGf4M4dyoKIhzdZyQ2bYQrjy
1014 Q4LB0lC7aOnsMyYKHHYeRvPxj
1015 IQXmdqgOJGq+vsevG06zW+1xg
1016 YJh9rCIfnm1GX/KMgxLPG2vXT
1017 D/RnLX+D3T3UL7HJYHJhAZD5L
1018 59VvjSPsZJHeDCUyWYrvPZesZ
1019 DIRvhDD52SKvbheeTJUm6Ehkz
1020 ytNN2SN96QRk8j/iI8ib";
1026 dnssec-validation yes;
1029 <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
1030 <h3 class="title">Note</h3>
1031 None of the keys listed in this example are valid. In particular,
1032 the root key is not valid.
1035 When DNSSEC validation is enabled and properly configured,
1036 the resolver will reject any answers from signed, secure zones
1037 which fail to validate, and will return SERVFAIL to the client.
1040 Responses may fail to validate for any of several reasons,
1041 including missing, expired, or invalid signatures, a key which
1042 does not match the DS RRset in the parent zone, or an insecure
1043 response from a zone which, according to its parent, should have
1046 <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
1047 <h3 class="title">Note</h3>
1049 When the validator receives a response from an unsigned zone
1050 that has a signed parent, it must confirm with the parent
1051 that the zone was intentionally left unsigned. It does
1052 this by verifying, via signed and validated NSEC/NSEC3 records,
1053 that the parent zone contains no DS records for the child.
1056 If the validator <span class="emphasis"><em>can</em></span> prove that the zone
1057 is insecure, then the response is accepted. However, if it
1058 cannot, then it must assume an insecure response to be a
1059 forgery; it rejects the response and logs an error.
1062 The logged error reads "insecurity proof failed" and
1063 "got insecure response; parent indicates it should be secure".
1064 (Prior to BIND 9.7, the logged error was "not insecure".
1065 This referred to the zone, not the response.)
1070 <div class="sect1" lang="en">
1071 <div class="titlepage"><div><div><h2 class="title" style="clear: both">
1072 <a name="dnssec.dynamic.zones"></a>DNSSEC, Dynamic Zones, and Automatic Signing</h2></div></div></div>
1073 <p>As of BIND 9.7.0 it is possible to change a dynamic zone
1074 from insecure to signed and back again. A secure zone can use
1075 either NSEC or NSEC3 chains.</p>
1076 <div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title">
1077 <a name="id2610615"></a>Converting from insecure to secure</h3></div></div></div></div>
1078 <p>Changing a zone from insecure to secure can be done in two
1079 ways: using a dynamic DNS update, or the
1080 <span><strong class="command">auto-dnssec</strong></span> zone option.</p>
1081 <p>For either method, you need to configure
1082 <span><strong class="command">named</strong></span> so that it can see the
1083 <code class="filename">K*</code> files which contain the public and private
1084 parts of the keys that will be used to sign the zone. These files
1085 will have been generated by
1086 <span><strong class="command">dnssec-keygen</strong></span>. You can do this by placing them
1087 in the key-directory, as specified in
1088 <code class="filename">named.conf</code>:</p>
1089 <pre class="programlisting">
1092 update-policy local;
1093 file "dynamic/example.net/example.net";
1094 key-directory "dynamic/example.net";
1097 <p>If one KSK and one ZSK DNSKEY key have been generated, this
1098 configuration will cause all records in the zone to be signed
1099 with the ZSK, and the DNSKEY RRset to be signed with the KSK as
1100 well. An NSEC chain will be generated as part of the initial
1101 signing process.</p>
1102 <div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title">
1103 <a name="id2610652"></a>Dynamic DNS update method</h3></div></div></div></div>
1104 <p>To insert the keys via dynamic update:</p>
1105 <pre class="screen">
1108 > update add example.net DNSKEY 256 3 7 AwEAAZn17pUF0KpbPA2c7Gz76Vb18v0teKT3EyAGfBfL8eQ8al35zz3Y I1m/SAQBxIqMfLtIwqWPdgthsu36azGQAX8=
1109 > update add example.net DNSKEY 257 3 7 AwEAAd/7odU/64o2LGsifbLtQmtO8dFDtTAZXSX2+X3e/UNlq9IHq3Y0 XtC0Iuawl/qkaKVxXe2lo8Ct+dM6UehyCqk=
1112 <p>While the update request will complete almost immediately,
1113 the zone will not be completely signed until
1114 <span><strong class="command">named</strong></span> has had time to walk the zone and
1115 generate the NSEC and RRSIG records. The NSEC record at the apex
1116 will be added last, to signal that there is a complete NSEC
1118 <p>If you wish to sign using NSEC3 instead of NSEC, you should
1119 add an NSEC3PARAM record to the initial update request. If you
1120 wish the NSEC3 chain to have the OPTOUT bit set, set it in the
1121 flags field of the NSEC3PARAM record.</p>
1122 <pre class="screen">
1125 > update add example.net DNSKEY 256 3 7 AwEAAZn17pUF0KpbPA2c7Gz76Vb18v0teKT3EyAGfBfL8eQ8al35zz3Y I1m/SAQBxIqMfLtIwqWPdgthsu36azGQAX8=
1126 > update add example.net DNSKEY 257 3 7 AwEAAd/7odU/64o2LGsifbLtQmtO8dFDtTAZXSX2+X3e/UNlq9IHq3Y0 XtC0Iuawl/qkaKVxXe2lo8Ct+dM6UehyCqk=
1127 > update add example.net NSEC3PARAM 1 1 100 1234567890
1130 <p>Again, this update request will complete almost
1131 immediately; however, the record won't show up until
1132 <span><strong class="command">named</strong></span> has had a chance to build/remove the
1133 relevant chain. A private type record will be created to record
1134 the state of the operation (see below for more details), and will
1135 be removed once the operation completes.</p>
1136 <p>While the initial signing and NSEC/NSEC3 chain generation
1137 is happening, other updates are possible as well.</p>
1138 <div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title">
1139 <a name="id2563653"></a>Fully automatic zone signing</h3></div></div></div></div>
1140 <p>To enable automatic signing, add the
1141 <span><strong class="command">auto-dnssec</strong></span> option to the zone statement in
1142 <code class="filename">named.conf</code>.
1143 <span><strong class="command">auto-dnssec</strong></span> has two possible arguments:
1144 <code class="constant">allow</code> or
1145 <code class="constant">maintain</code>.</p>
1147 <span><strong class="command">auto-dnssec allow</strong></span>,
1148 <span><strong class="command">named</strong></span> can search the key directory for keys
1149 matching the zone, insert them into the zone, and use them to
1150 sign the zone. It will do so only when it receives an
1151 <span><strong class="command">rndc sign <zonename></strong></span>.</p>
1154 <span><strong class="command">auto-dnssec maintain</strong></span> includes the above
1155 functionality, but will also automatically adjust the zone's
1156 DNSKEY records on schedule according to the keys' timing metadata.
1157 (See <a href="man.dnssec-keygen.html" title="dnssec-keygen"><span class="refentrytitle"><span class="application">dnssec-keygen</span></span>(8)</a> and
1158 <a href="man.dnssec-settime.html" title="dnssec-settime"><span class="refentrytitle"><span class="application">dnssec-settime</span></span>(8)</a> for more information.)
1161 <span><strong class="command">named</strong></span> will periodically search the key directory
1162 for keys matching the zone, and if the keys' metadata indicates
1163 that any change should be made the zone, such as adding, removing,
1164 or revoking a key, then that action will be carried out. By default,
1165 the key directory is checked for changes every 60 minutes; this period
1166 can be adjusted with the <code class="option">dnssec-loadkeys-interval</code>, up
1167 to a maximum of 24 hours. The <span><strong class="command">rndc loadkeys</strong></span> forces
1168 <span><strong class="command">named</strong></span> to check for key updates immediately.
1171 If keys are present in the key directory the first time the zone
1172 is loaded, the zone will be signed immediately, without waiting for an
1173 <span><strong class="command">rndc sign</strong></span> or <span><strong class="command">rndc loadkeys</strong></span>
1174 command. (Those commands can still be used when there are unscheduled
1175 key changes, however.)
1178 When new keys are added to a zone, the TTL is set to match that
1179 of any existing DNSKEY RRset. If there is no existing DNSKEY RRset,
1180 then the TTL will be set to the TTL specified when the key was
1181 created (using the <span><strong class="command">dnssec-keygen -L</strong></span> option), if
1182 any, or to the SOA TTL.
1185 If you wish the zone to be signed using NSEC3 instead of NSEC,
1186 submit an NSEC3PARAM record via dynamic update prior to the
1187 scheduled publication and activation of the keys. If you wish the
1188 NSEC3 chain to have the OPTOUT bit set, set it in the flags field
1189 of the NSEC3PARAM record. The NSEC3PARAM record will not appear in
1190 the zone immediately, but it will be stored for later reference. When
1191 the zone is signed and the NSEC3 chain is completed, the NSEC3PARAM
1192 record will appear in the zone.
1195 <span><strong class="command">auto-dnssec</strong></span> option requires the zone to be
1196 configured to allow dynamic updates, by adding an
1197 <span><strong class="command">allow-update</strong></span> or
1198 <span><strong class="command">update-policy</strong></span> statement to the zone
1199 configuration. If this has not been done, the configuration will
1201 <div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title">
1202 <a name="id2563900"></a>Private-type records</h3></div></div></div></div>
1203 <p>The state of the signing process is signaled by
1204 private-type records (with a default type value of 65534). When
1205 signing is complete, these records will have a nonzero value for
1206 the final octet (for those records which have a nonzero initial
1208 <p>The private type record format: If the first octet is
1209 non-zero then the record indicates that the zone needs to be
1210 signed with the key matching the record, or that all signatures
1211 that match the record should be removed.</p>
1214 <div class="literallayout"><p><br>
1216 algorithm (octet 1)<br>
1217 key id in network order (octet 2 and 3)<br>
1218 removal flag (octet 4)<br>
1219 complete flag (octet 5)<br>
1223 <p>Only records flagged as "complete" can be removed via
1224 dynamic update. Attempts to remove other private type records
1225 will be silently ignored.</p>
1226 <p>If the first octet is zero (this is a reserved algorithm
1227 number that should never appear in a DNSKEY record) then the
1228 record indicates changes to the NSEC3 chains are in progress. The
1229 rest of the record contains an NSEC3PARAM record. The flag field
1230 tells what operation to perform based on the flag bits.</p>
1233 <div class="literallayout"><p><br>
1242 <div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title">
1243 <a name="id2563938"></a>DNSKEY rollovers</h3></div></div></div></div>
1244 <p>As with insecure-to-secure conversions, rolling DNSSEC
1245 keys can be done in two ways: using a dynamic DNS update, or the
1246 <span><strong class="command">auto-dnssec</strong></span> zone option.</p>
1247 <div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title">
1248 <a name="id2563950"></a>Dynamic DNS update method</h3></div></div></div></div>
1249 <p> To perform key rollovers via dynamic update, you need to add
1250 the <code class="filename">K*</code> files for the new keys so that
1251 <span><strong class="command">named</strong></span> can find them. You can then add the new
1252 DNSKEY RRs via dynamic update.
1253 <span><strong class="command">named</strong></span> will then cause the zone to be signed
1254 with the new keys. When the signing is complete the private type
1255 records will be updated so that the last octet is non
1257 <p>If this is for a KSK you need to inform the parent and any
1258 trust anchor repositories of the new KSK.</p>
1259 <p>You should then wait for the maximum TTL in the zone before
1260 removing the old DNSKEY. If it is a KSK that is being updated,
1261 you also need to wait for the DS RRset in the parent to be
1262 updated and its TTL to expire. This ensures that all clients will
1263 be able to verify at least one signature when you remove the old
1265 <p>The old DNSKEY can be removed via UPDATE. Take care to
1266 specify the correct key.
1267 <span><strong class="command">named</strong></span> will clean out any signatures generated
1268 by the old key after the update completes.</p>
1269 <div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title">
1270 <a name="id2564052"></a>Automatic key rollovers</h3></div></div></div></div>
1271 <p>When a new key reaches its activation date (as set by
1272 <span><strong class="command">dnssec-keygen</strong></span> or <span><strong class="command">dnssec-settime</strong></span>),
1273 if the <span><strong class="command">auto-dnssec</strong></span> zone option is set to
1274 <code class="constant">maintain</code>, <span><strong class="command">named</strong></span> will
1275 automatically carry out the key rollover. If the key's algorithm
1276 has not previously been used to sign the zone, then the zone will
1277 be fully signed as quickly as possible. However, if the new key
1278 is replacing an existing key of the same algorithm, then the
1279 zone will be re-signed incrementally, with signatures from the
1280 old key being replaced with signatures from the new key as their
1281 signature validity periods expire. By default, this rollover
1282 completes in 30 days, after which it will be safe to remove the
1283 old key from the DNSKEY RRset.</p>
1284 <div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title">
1285 <a name="id2564078"></a>NSEC3PARAM rollovers via UPDATE</h3></div></div></div></div>
1286 <p>Add the new NSEC3PARAM record via dynamic update. When the
1287 new NSEC3 chain has been generated, the NSEC3PARAM flag field
1288 will be zero. At this point you can remove the old NSEC3PARAM
1289 record. The old chain will be removed after the update request
1291 <div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title">
1292 <a name="id2564088"></a>Converting from NSEC to NSEC3</h3></div></div></div></div>
1293 <p>To do this, you just need to add an NSEC3PARAM record. When
1294 the conversion is complete, the NSEC chain will have been removed
1295 and the NSEC3PARAM record will have a zero flag field. The NSEC3
1296 chain will be generated before the NSEC chain is
1298 <div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title">
1299 <a name="id2569832"></a>Converting from NSEC3 to NSEC</h3></div></div></div></div>
1300 <p>To do this, use <span><strong class="command">nsupdate</strong></span> to
1301 remove all NSEC3PARAM records with a zero flag
1302 field. The NSEC chain will be generated before the NSEC3 chain is
1304 <div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title">
1305 <a name="id2569845"></a>Converting from secure to insecure</h3></div></div></div></div>
1306 <p>To convert a signed zone to unsigned using dynamic DNS,
1307 delete all the DNSKEY records from the zone apex using
1308 <span><strong class="command">nsupdate</strong></span>. All signatures, NSEC or NSEC3 chains,
1309 and associated NSEC3PARAM records will be removed automatically.
1310 This will take place after the update request completes.</p>
1311 <p> This requires the
1312 <span><strong class="command">dnssec-secure-to-insecure</strong></span> option to be set to
1313 <strong class="userinput"><code>yes</code></strong> in
1314 <code class="filename">named.conf</code>.</p>
1315 <p>In addition, if the <span><strong class="command">auto-dnssec maintain</strong></span>
1316 zone statement is used, it should be removed or changed to
1317 <span><strong class="command">allow</strong></span> instead (or it will re-sign).
1319 <div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title">
1320 <a name="id2569882"></a>Periodic re-signing</h3></div></div></div></div>
1321 <p>In any secure zone which supports dynamic updates, named
1322 will periodically re-sign RRsets which have not been re-signed as
1323 a result of some update action. The signature lifetimes will be
1324 adjusted so as to spread the re-sign load over time rather than
1326 <div class="sect2" lang="en"><div class="titlepage"><div><div><h3 class="title">
1327 <a name="id2569892"></a>NSEC3 and OPTOUT</h3></div></div></div></div>
1329 <span><strong class="command">named</strong></span> only supports creating new NSEC3 chains
1330 where all the NSEC3 records in the zone have the same OPTOUT
1332 <span><strong class="command">named</strong></span> supports UPDATES to zones where the NSEC3
1333 records in the chain have mixed OPTOUT state.
1334 <span><strong class="command">named</strong></span> does not support changing the OPTOUT
1335 state of an individual NSEC3 record, the entire chain needs to be
1336 changed if the OPTOUT state of an individual NSEC3 needs to be
1339 <div class="sect1" lang="en">
1340 <div class="titlepage"><div><div><h2 class="title" style="clear: both">
1341 <a name="rfc5011.support"></a>Dynamic Trust Anchor Management</h2></div></div></div>
1342 <p>BIND 9.7.0 introduces support for RFC 5011, dynamic trust
1343 anchor management. Using this feature allows
1344 <span><strong class="command">named</strong></span> to keep track of changes to critical
1345 DNSSEC keys without any need for the operator to make changes to
1346 configuration files.</p>
1347 <div class="sect2" lang="en">
1348 <div class="titlepage"><div><div><h3 class="title">
1349 <a name="id2610129"></a>Validating Resolver</h3></div></div></div>
1350 <p>To configure a validating resolver to use RFC 5011 to
1351 maintain a trust anchor, configure the trust anchor using a
1352 <span><strong class="command">managed-keys</strong></span> statement. Information about
1353 this can be found in
1354 <a href="Bv9ARM.ch06.html#managed-keys" title="managed-keys Statement Definition
1355 and Usage">the section called “<span><strong class="command">managed-keys</strong></span> Statement Definition
1356 and Usage”</a>.</p>
1358 <div class="sect2" lang="en">
1359 <div class="titlepage"><div><div><h3 class="title">
1360 <a name="id2610151"></a>Authoritative Server</h3></div></div></div>
1361 <p>To set up an authoritative zone for RFC 5011 trust anchor
1362 maintenance, generate two (or more) key signing keys (KSKs) for
1363 the zone. Sign the zone with one of them; this is the "active"
1364 KSK. All KSK's which do not sign the zone are "stand-by"
1366 <p>Any validating resolver which is configured to use the
1367 active KSK as an RFC 5011-managed trust anchor will take note
1368 of the stand-by KSKs in the zone's DNSKEY RRset, and store them
1369 for future reference. The resolver will recheck the zone
1370 periodically, and after 30 days, if the new key is still there,
1371 then the key will be accepted by the resolver as a valid trust
1372 anchor for the zone. Any time after this 30-day acceptance
1373 timer has completed, the active KSK can be revoked, and the
1374 zone can be "rolled over" to the newly accepted key.</p>
1375 <p>The easiest way to place a stand-by key in a zone is to
1376 use the "smart signing" features of
1377 <span><strong class="command">dnssec-keygen</strong></span> and
1378 <span><strong class="command">dnssec-signzone</strong></span>. If a key with a publication
1379 date in the past, but an activation date which is unset or in
1381 <span><strong class="command">dnssec-signzone -S</strong></span>" will include the DNSKEY
1382 record in the zone, but will not sign with it:</p>
1383 <pre class="screen">
1384 $ <strong class="userinput"><code>dnssec-keygen -K keys -f KSK -P now -A now+2y example.net</code></strong>
1385 $ <strong class="userinput"><code>dnssec-signzone -S -K keys example.net</code></strong>
1387 <p>To revoke a key, the new command
1388 <span><strong class="command">dnssec-revoke</strong></span> has been added. This adds the
1389 REVOKED bit to the key flags and re-generates the
1390 <code class="filename">K*.key</code> and
1391 <code class="filename">K*.private</code> files.</p>
1392 <p>After revoking the active key, the zone must be signed
1393 with both the revoked KSK and the new active KSK. (Smart
1394 signing takes care of this automatically.)</p>
1395 <p>Once a key has been revoked and used to sign the DNSKEY
1396 RRset in which it appears, that key will never again be
1397 accepted as a valid trust anchor by the resolver. However,
1398 validation can proceed using the new active key (which had been
1399 accepted by the resolver when it was a stand-by key).</p>
1400 <p>See RFC 5011 for more details on key rollover
1402 <p>When a key has been revoked, its key ID changes,
1403 increasing by 128, and wrapping around at 65535. So, for
1404 example, the key "<code class="filename">Kexample.com.+005+10000</code>" becomes
1405 "<code class="filename">Kexample.com.+005+10128</code>".</p>
1406 <p>If two keys have ID's exactly 128 apart, and one is
1407 revoked, then the two key ID's will collide, causing several
1408 problems. To prevent this,
1409 <span><strong class="command">dnssec-keygen</strong></span> will not generate a new key if
1410 another key is present which may collide. This checking will
1411 only occur if the new keys are written to the same directory
1412 which holds all other keys in use for that zone.</p>
1413 <p>Older versions of BIND 9 did not have this precaution.
1414 Exercise caution if using key revocation on keys that were
1415 generated by previous releases, or if using keys stored in
1416 multiple directories or on multiple machines.</p>
1417 <p>It is expected that a future release of BIND 9 will
1418 address this problem in a different way, by storing revoked
1419 keys with their original unrevoked key ID's.</p>
1422 <div class="sect1" lang="en">
1423 <div class="titlepage"><div><div><h2 class="title" style="clear: both">
1424 <a name="pkcs11"></a>PKCS #11 (Cryptoki) support</h2></div></div></div>
1425 <p>PKCS #11 (Public Key Cryptography Standard #11) defines a
1426 platform- independent API for the control of hardware security
1427 modules (HSMs) and other cryptographic support devices.</p>
1428 <p>BIND 9 is known to work with two HSMs: The Sun SCA 6000
1429 cryptographic acceleration board, tested under Solaris x86, and
1430 the AEP Keyper network-attached key storage device, tested with
1431 Debian Linux, Solaris x86 and Windows Server 2003.</p>
1432 <div class="sect2" lang="en">
1433 <div class="titlepage"><div><div><h3 class="title">
1434 <a name="id2613326"></a>Prerequisites</h3></div></div></div>
1435 <p>See the HSM vendor documentation for information about
1436 installing, initializing, testing and troubleshooting the
1438 <p>BIND 9 uses OpenSSL for cryptography, but stock OpenSSL
1439 does not yet fully support PKCS #11. However, a PKCS #11 engine
1440 for OpenSSL is available from the OpenSolaris project. It has
1441 been modified by ISC to work with with BIND 9, and to provide
1442 new features such as PIN management and key by
1444 <p>The patched OpenSSL depends on a "PKCS #11 provider".
1445 This is a shared library object, providing a low-level PKCS #11
1446 interface to the HSM hardware. It is dynamically loaded by
1447 OpenSSL at runtime. The PKCS #11 provider comes from the HSM
1448 vendor, and is specific to the HSM to be controlled.</p>
1449 <p>There are two "flavors" of PKCS #11 support provided by
1450 the patched OpenSSL, one of which must be chosen at
1451 configuration time. The correct choice depends on the HSM
1453 <div class="itemizedlist"><ul type="disc">
1454 <li><p>Use 'crypto-accelerator' with HSMs that have hardware
1455 cryptographic acceleration features, such as the SCA 6000
1456 board. This causes OpenSSL to run all supported
1457 cryptographic operations in the HSM.</p></li>
1458 <li><p>Use 'sign-only' with HSMs that are designed to
1459 function primarily as secure key storage devices, but lack
1460 hardware acceleration. These devices are highly secure, but
1461 are not necessarily any faster at cryptography than the
1462 system CPU — often, they are slower. It is therefore
1463 most efficient to use them only for those cryptographic
1464 functions that require access to the secured private key,
1465 such as zone signing, and to use the system CPU for all
1466 other computationally-intensive operations. The AEP Keyper
1467 is an example of such a device.</p></li>
1470 The modified OpenSSL code is included in the BIND 9 release,
1471 in the form of a context diff against the latest versions of
1472 OpenSSL. OpenSSL 0.9.8, 1.0.0, and 1.0.1 are supported; there are
1473 separate diffs for each version. In the examples to follow,
1474 we use OpenSSL 0.9.8, but the same methods work with OpenSSL
1477 <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
1478 <h3 class="title">Note</h3>
1479 The latest OpenSSL versions at the time of the BIND release
1480 are 0.9.8y, 1.0.0k and 1.0.1e.
1481 ISC will provide an updated patch as new versions of OpenSSL
1482 are released. The version number in the following examples
1483 is expected to change.</div>
1485 Before building BIND 9 with PKCS #11 support, it will be
1486 necessary to build OpenSSL with this patch in place and inform
1487 it of the path to the HSM-specific PKCS #11 provider
1489 <p>Obtain OpenSSL 0.9.8s:</p>
1490 <pre class="screen">
1491 $ <strong class="userinput"><code>wget <a href="" target="_top">http://www.openssl.org/source/openssl-0.9.8s.tar.gz</a></code></strong>
1493 <p>Extract the tarball:</p>
1494 <pre class="screen">
1495 $ <strong class="userinput"><code>tar zxf openssl-0.9.8s.tar.gz</code></strong>
1497 <p>Apply the patch from the BIND 9 release:</p>
1498 <pre class="screen">
1499 $ <strong class="userinput"><code>patch -p1 -d openssl-0.9.8s \
1500 < bind9/bin/pkcs11/openssl-0.9.8s-patch</code></strong>
1502 <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
1503 <h3 class="title">Note</h3>(Note that the patch file may not be compatible with the
1504 "patch" utility on all operating systems. You may need to
1505 install GNU patch.)</div>
1506 <p>When building OpenSSL, place it in a non-standard
1507 location so that it does not interfere with OpenSSL libraries
1508 elsewhere on the system. In the following examples, we choose
1509 to install into "/opt/pkcs11/usr". We will use this location
1510 when we configure BIND 9.</p>
1511 <div class="sect3" lang="en">
1512 <div class="titlepage"><div><div><h4 class="title">
1513 <a name="id2610828"></a>Building OpenSSL for the AEP Keyper on Linux</h4></div></div></div>
1514 <p>The AEP Keyper is a highly secure key storage device,
1515 but does not provide hardware cryptographic acceleration. It
1516 can carry out cryptographic operations, but it is probably
1517 slower than your system's CPU. Therefore, we choose the
1518 'sign-only' flavor when building OpenSSL.</p>
1519 <p>The Keyper-specific PKCS #11 provider library is
1520 delivered with the Keyper software. In this example, we place
1521 it /opt/pkcs11/usr/lib:</p>
1522 <pre class="screen">
1523 $ <strong class="userinput"><code>cp pkcs11.GCC4.0.2.so.4.05 /opt/pkcs11/usr/lib/libpkcs11.so</code></strong>
1525 <p>This library is only available for Linux as a 32-bit
1526 binary. If we are compiling on a 64-bit Linux system, it is
1527 necessary to force a 32-bit build, by specifying -m32 in the
1529 <p>Finally, the Keyper library requires threads, so we
1530 must specify -pthread.</p>
1531 <pre class="screen">
1532 $ <strong class="userinput"><code>cd openssl-0.9.8s</code></strong>
1533 $ <strong class="userinput"><code>./Configure linux-generic32 -m32 -pthread \
1534 --pk11-libname=/opt/pkcs11/usr/lib/libpkcs11.so \
1535 --pk11-flavor=sign-only \
1536 --prefix=/opt/pkcs11/usr</code></strong>
1538 <p>After configuring, run "<span><strong class="command">make</strong></span>"
1539 and "<span><strong class="command">make test</strong></span>". If "<span><strong class="command">make
1540 test</strong></span>" fails with "pthread_atfork() not found", you forgot to
1541 add the -pthread above.</p>
1543 <div class="sect3" lang="en">
1544 <div class="titlepage"><div><div><h4 class="title">
1545 <a name="id2610898"></a>Building OpenSSL for the SCA 6000 on Solaris</h4></div></div></div>
1546 <p>The SCA-6000 PKCS #11 provider is installed as a system
1547 library, libpkcs11. It is a true crypto accelerator, up to 4
1548 times faster than any CPU, so the flavor shall be
1549 'crypto-accelerator'.</p>
1550 <p>In this example, we are building on Solaris x86 on an
1552 <pre class="screen">
1553 $ <strong class="userinput"><code>cd openssl-0.9.8s</code></strong>
1554 $ <strong class="userinput"><code>./Configure solaris64-x86_64-cc \
1555 --pk11-libname=/usr/lib/64/libpkcs11.so \
1556 --pk11-flavor=crypto-accelerator \
1557 --prefix=/opt/pkcs11/usr</code></strong>
1559 <p>(For a 32-bit build, use "solaris-x86-cc" and
1560 /usr/lib/libpkcs11.so.)</p>
1561 <p>After configuring, run
1562 <span><strong class="command">make</strong></span> and
1563 <span><strong class="command">make test</strong></span>.</p>
1565 <div class="sect3" lang="en">
1566 <div class="titlepage"><div><div><h4 class="title">
1567 <a name="id2611015"></a>Building OpenSSL for SoftHSM</h4></div></div></div>
1568 <p>SoftHSM is a software library provided by the OpenDNSSEC
1569 project (http://www.opendnssec.org) which provides a PKCS#11
1570 interface to a virtual HSM, implemented in the form of encrypted
1571 data on the local filesystem. It uses the Botan library for
1572 encryption and SQLite3 for data storage. Though less secure
1573 than a true HSM, it can provide more secure key storage than
1574 traditional key files, and can allow you to experiment with
1575 PKCS#11 when an HSM is not available.</p>
1576 <p>The SoftHSM cryptographic store must be installed and
1577 initialized before using it with OpenSSL, and the SOFTHSM_CONF
1578 environment variable must always point to the SoftHSM configuration
1580 <pre class="screen">
1581 $ <strong class="userinput"><code> cd softhsm-1.3.0 </code></strong>
1582 $ <strong class="userinput"><code> configure --prefix=/opt/pkcs11/usr </code></strong>
1583 $ <strong class="userinput"><code> make </code></strong>
1584 $ <strong class="userinput"><code> make install </code></strong>
1585 $ <strong class="userinput"><code> export SOFTHSM_CONF=/opt/pkcs11/softhsm.conf </code></strong>
1586 $ <strong class="userinput"><code> echo "0:/opt/pkcs11/softhsm.db" > $SOFTHSM_CONF </code></strong>
1587 $ <strong class="userinput"><code> /opt/pkcs11/usr/bin/softhsm --init-token 0 --slot 0 --label softhsm </code></strong>
1589 <p>SoftHSM can perform all cryptographic operations, but
1590 since it only uses your system CPU, there is no need to use it
1591 for anything but signing. Therefore, we choose the 'sign-only'
1592 flavor when building OpenSSL.</p>
1593 <pre class="screen">
1594 $ <strong class="userinput"><code>cd openssl-0.9.8s</code></strong>
1595 $ <strong class="userinput"><code>./Configure linux-x86_64 -pthread \
1596 --pk11-libname=/opt/pkcs11/usr/lib/libpkcs11.so \
1597 --pk11-flavor=sign-only \
1598 --prefix=/opt/pkcs11/usr</code></strong>
1600 <p>After configuring, run "<span><strong class="command">make</strong></span>"
1601 and "<span><strong class="command">make test</strong></span>".</p>
1603 <p>Once you have built OpenSSL, run
1604 "<span><strong class="command">apps/openssl engine pkcs11</strong></span>" to confirm
1605 that PKCS #11 support was compiled in correctly. The output
1606 should be one of the following lines, depending on the flavor
1608 <pre class="screen">
1609 (pkcs11) PKCS #11 engine support (sign only)
1612 <pre class="screen">
1613 (pkcs11) PKCS #11 engine support (crypto accelerator)
1616 "<span><strong class="command">apps/openssl engine pkcs11 -t</strong></span>". This will
1617 attempt to initialize the PKCS #11 engine. If it is able to
1618 do so successfully, it will report
1619 “<span class="quote"><code class="literal">[ available ]</code></span>”.</p>
1620 <p>If the output is correct, run
1621 "<span><strong class="command">make install</strong></span>" which will install the
1622 modified OpenSSL suite to
1623 <code class="filename">/opt/pkcs11/usr</code>.</p>
1625 <div class="sect2" lang="en">
1626 <div class="titlepage"><div><div><h3 class="title">
1627 <a name="id2611166"></a>Building BIND 9 with PKCS#11</h3></div></div></div>
1628 <p>When building BIND 9, the location of the custom-built
1629 OpenSSL library must be specified via configure.</p>
1630 <div class="sect3" lang="en">
1631 <div class="titlepage"><div><div><h4 class="title">
1632 <a name="id2611175"></a>Configuring BIND 9 for Linux with the AEP Keyper</h4></div></div></div>
1633 <p>To link with the PKCS #11 provider, threads must be
1634 enabled in the BIND 9 build.</p>
1635 <p>The PKCS #11 library for the AEP Keyper is currently
1636 only available as a 32-bit binary. If we are building on a
1637 64-bit host, we must force a 32-bit build by adding "-m32" to
1638 the CC options on the "configure" command line.</p>
1639 <pre class="screen">
1640 $ <strong class="userinput"><code>cd ../bind9</code></strong>
1641 $ <strong class="userinput"><code>./configure CC="gcc -m32" --enable-threads \
1642 --with-openssl=/opt/pkcs11/usr \
1643 --with-pkcs11=/opt/pkcs11/usr/lib/libpkcs11.so</code></strong>
1646 <div class="sect3" lang="en">
1647 <div class="titlepage"><div><div><h4 class="title">
1648 <a name="id2611275"></a>Configuring BIND 9 for Solaris with the SCA 6000</h4></div></div></div>
1649 <p>To link with the PKCS #11 provider, threads must be
1650 enabled in the BIND 9 build.</p>
1651 <pre class="screen">
1652 $ <strong class="userinput"><code>cd ../bind9</code></strong>
1653 $ <strong class="userinput"><code>./configure CC="cc -xarch=amd64" --enable-threads \
1654 --with-openssl=/opt/pkcs11/usr \
1655 --with-pkcs11=/usr/lib/64/libpkcs11.so</code></strong>
1657 <p>(For a 32-bit build, omit CC="cc -xarch=amd64".)</p>
1658 <p>If configure complains about OpenSSL not working, you
1659 may have a 32/64-bit architecture mismatch. Or, you may have
1660 incorrectly specified the path to OpenSSL (it should be the
1661 same as the --prefix argument to the OpenSSL
1664 <div class="sect3" lang="en">
1665 <div class="titlepage"><div><div><h4 class="title">
1666 <a name="id2611312"></a>Configuring BIND 9 for SoftHSM</h4></div></div></div>
1667 <pre class="screen">
1668 $ <strong class="userinput"><code>cd ../bind9</code></strong>
1669 $ <strong class="userinput"><code>./configure --enable-threads \
1670 --with-openssl=/opt/pkcs11/usr \
1671 --with-pkcs11=/opt/pkcs11/usr/lib/libpkcs11.so</code></strong>
1674 <p>After configuring, run
1675 "<span><strong class="command">make</strong></span>",
1676 "<span><strong class="command">make test</strong></span>" and
1677 "<span><strong class="command">make install</strong></span>".</p>
1678 <p>(Note: If "make test" fails in the "pkcs11" system test, you may
1679 have forgotten to set the SOFTHSM_CONF environment variable.)</p>
1681 <div class="sect2" lang="en">
1682 <div class="titlepage"><div><div><h3 class="title">
1683 <a name="id2613408"></a>PKCS #11 Tools</h3></div></div></div>
1684 <p>BIND 9 includes a minimal set of tools to operate the
1686 <span><strong class="command">pkcs11-keygen</strong></span> to generate a new key pair
1688 <span><strong class="command">pkcs11-list</strong></span> to list objects currently
1690 <span><strong class="command">pkcs11-destroy</strong></span> to remove objects.</p>
1691 <p>In UNIX/Linux builds, these tools are built only if BIND
1692 9 is configured with the --with-pkcs11 option. (NOTE: If
1693 --with-pkcs11 is set to "yes", rather than to the path of the
1694 PKCS #11 provider, then the tools will be built but the
1695 provider will be left undefined. Use the -m option or the
1696 PKCS11_PROVIDER environment variable to specify the path to the
1699 <div class="sect2" lang="en">
1700 <div class="titlepage"><div><div><h3 class="title">
1701 <a name="id2613438"></a>Using the HSM</h3></div></div></div>
1702 <p>First, we must set up the runtime environment so the
1703 OpenSSL and PKCS #11 libraries can be loaded:</p>
1704 <pre class="screen">
1705 $ <strong class="userinput"><code>export LD_LIBRARY_PATH=/opt/pkcs11/usr/lib:${LD_LIBRARY_PATH}</code></strong>
1707 <p>When operating an AEP Keyper, it is also necessary to
1708 specify the location of the "machine" file, which stores
1709 information about the Keyper for use by PKCS #11 provider
1710 library. If the machine file is in
1711 <code class="filename">/opt/Keyper/PKCS11Provider/machine</code>,
1713 <pre class="screen">
1714 $ <strong class="userinput"><code>export KEYPER_LIBRARY_PATH=/opt/Keyper/PKCS11Provider</code></strong>
1716 <p>These environment variables must be set whenever running
1717 any tool that uses the HSM, including
1718 <span><strong class="command">pkcs11-keygen</strong></span>,
1719 <span><strong class="command">pkcs11-list</strong></span>,
1720 <span><strong class="command">pkcs11-destroy</strong></span>,
1721 <span><strong class="command">dnssec-keyfromlabel</strong></span>,
1722 <span><strong class="command">dnssec-signzone</strong></span>,
1723 <span><strong class="command">dnssec-keygen</strong></span>(which will use the HSM for
1724 random number generation), and
1725 <span><strong class="command">named</strong></span>.</p>
1726 <p>We can now create and use keys in the HSM. In this case,
1727 we will create a 2048 bit key and give it the label
1729 <pre class="screen">
1730 $ <strong class="userinput"><code>pkcs11-keygen -b 2048 -l sample-ksk</code></strong>
1732 <p>To confirm that the key exists:</p>
1733 <pre class="screen">
1734 $ <strong class="userinput"><code>pkcs11-list</code></strong>
1736 object[0]: handle 2147483658 class 3 label[8] 'sample-ksk' id[0]
1737 object[1]: handle 2147483657 class 2 label[8] 'sample-ksk' id[0]
1739 <p>Before using this key to sign a zone, we must create a
1740 pair of BIND 9 key files. The "dnssec-keyfromlabel" utility
1741 does this. In this case, we will be using the HSM key
1742 "sample-ksk" as the key-signing key for "example.net":</p>
1743 <pre class="screen">
1744 $ <strong class="userinput"><code>dnssec-keyfromlabel -l sample-ksk -f KSK example.net</code></strong>
1746 <p>The resulting K*.key and K*.private files can now be used
1747 to sign the zone. Unlike normal K* files, which contain both
1748 public and private key data, these files will contain only the
1749 public key data, plus an identifier for the private key which
1750 remains stored within the HSM. The HSM handles signing with the
1752 <p>If you wish to generate a second key in the HSM for use
1753 as a zone-signing key, follow the same procedure above, using a
1754 different keylabel, a smaller key size, and omitting "-f KSK"
1755 from the dnssec-keyfromlabel arguments:</p>
1756 <pre class="screen">
1757 $ <strong class="userinput"><code>pkcs11-keygen -b 1024 -l sample-zsk</code></strong>
1758 $ <strong class="userinput"><code>dnssec-keyfromlabel -l sample-zsk example.net</code></strong>
1760 <p>Alternatively, you may prefer to generate a conventional
1761 on-disk key, using dnssec-keygen:</p>
1762 <pre class="screen">
1763 $ <strong class="userinput"><code>dnssec-keygen example.net</code></strong>
1765 <p>This provides less security than an HSM key, but since
1766 HSMs can be slow or cumbersome to use for security reasons, it
1767 may be more efficient to reserve HSM keys for use in the less
1768 frequent key-signing operation. The zone-signing key can be
1769 rolled more frequently, if you wish, to compensate for a
1770 reduction in key security.</p>
1771 <p>Now you can sign the zone. (Note: If not using the -S
1773 <span><strong class="command">dnssec-signzone</strong></span>, it will be necessary to add
1774 the contents of both
1775 <code class="filename">K*.key</code> files to the zone master file before
1777 <pre class="screen">
1778 $ <strong class="userinput"><code>dnssec-signzone -S example.net</code></strong>
1780 Verifying the zone using the following algorithms:
1782 Zone signing complete:
1783 Algorithm: NSEC3RSASHA1: ZSKs: 1, KSKs: 1 active, 0 revoked, 0 stand-by
1787 <div class="sect2" lang="en">
1788 <div class="titlepage"><div><div><h3 class="title">
1789 <a name="id2637735"></a>Specifying the engine on the command line</h3></div></div></div>
1790 <p>The OpenSSL engine can be specified in
1791 <span><strong class="command">named</strong></span> and all of the BIND
1792 <span><strong class="command">dnssec-*</strong></span> tools by using the "-E
1793 <engine>" command line option. If BIND 9 is built with
1794 the --with-pkcs11 option, this option defaults to "pkcs11".
1795 Specifying the engine will generally not be necessary unless
1796 for some reason you wish to use a different OpenSSL
1798 <p>If you wish to disable use of the "pkcs11" engine —
1799 for troubleshooting purposes, or because the HSM is unavailable
1800 — set the engine to the empty string. For example:</p>
1801 <pre class="screen">
1802 $ <strong class="userinput"><code>dnssec-signzone -E '' -S example.net</code></strong>
1805 <span><strong class="command">dnssec-signzone</strong></span> to run as if it were compiled
1806 without the --with-pkcs11 option.</p>
1808 <div class="sect2" lang="en">
1809 <div class="titlepage"><div><div><h3 class="title">
1810 <a name="id2637781"></a>Running named with automatic zone re-signing</h3></div></div></div>
1812 <span><strong class="command">named</strong></span> to dynamically re-sign zones using HSM
1813 keys, and/or to to sign new records inserted via nsupdate, then
1814 named must have access to the HSM PIN. This can be accomplished
1815 by placing the PIN into the openssl.cnf file (in the above
1817 <code class="filename">/opt/pkcs11/usr/ssl/openssl.cnf</code>).</p>
1818 <p>The location of the openssl.cnf file can be overridden by
1819 setting the OPENSSL_CONF environment variable before running
1821 <p>Sample openssl.cnf:</p>
1822 <pre class="programlisting">
1823 openssl_conf = openssl_def
1825 engines = engine_section
1827 pkcs11 = pkcs11_section
1829 PIN = <em class="replaceable"><code><PLACE PIN HERE></code></em>
1831 <p>This will also allow the dnssec-* tools to access the HSM
1832 without PIN entry. (The pkcs11-* tools access the HSM directly,
1833 not via OpenSSL, so a PIN will still be required to use
1835 <div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;">
1836 <h3 class="title">Warning</h3>
1837 <p>Placing the HSM's PIN in a text file in
1838 this manner may reduce the security advantage of using an
1839 HSM. Be sure this is what you want to do before configuring
1840 OpenSSL in this way.</p>
1844 <div class="sect1" lang="en">
1845 <div class="titlepage"><div><div><h2 class="title" style="clear: both">
1846 <a name="id2571571"></a>IPv6 Support in <acronym class="acronym">BIND</acronym> 9</h2></div></div></div>
1848 <acronym class="acronym">BIND</acronym> 9 fully supports all currently
1849 defined forms of IPv6 name to address and address to name
1850 lookups. It will also use IPv6 addresses to make queries when
1851 running on an IPv6 capable system.
1854 For forward lookups, <acronym class="acronym">BIND</acronym> 9 supports
1855 only AAAA records. RFC 3363 deprecated the use of A6 records,
1856 and client-side support for A6 records was accordingly removed
1857 from <acronym class="acronym">BIND</acronym> 9.
1858 However, authoritative <acronym class="acronym">BIND</acronym> 9 name servers still
1859 load zone files containing A6 records correctly, answer queries
1860 for A6 records, and accept zone transfer for a zone containing A6
1864 For IPv6 reverse lookups, <acronym class="acronym">BIND</acronym> 9 supports
1865 the traditional "nibble" format used in the
1866 <span class="emphasis"><em>ip6.arpa</em></span> domain, as well as the older, deprecated
1867 <span class="emphasis"><em>ip6.int</em></span> domain.
1868 Older versions of <acronym class="acronym">BIND</acronym> 9
1869 supported the "binary label" (also known as "bitstring") format,
1870 but support of binary labels has been completely removed per
1872 Many applications in <acronym class="acronym">BIND</acronym> 9 do not understand
1873 the binary label format at all any more, and will return an
1875 In particular, an authoritative <acronym class="acronym">BIND</acronym> 9
1876 name server will not load a zone file containing binary labels.
1879 For an overview of the format and structure of IPv6 addresses,
1880 see <a href="Bv9ARM.ch11.html#ipv6addresses" title="IPv6 addresses (AAAA)">the section called “IPv6 addresses (AAAA)”</a>.
1882 <div class="sect2" lang="en">
1883 <div class="titlepage"><div><div><h3 class="title">
1884 <a name="id2571837"></a>Address Lookups Using AAAA Records</h3></div></div></div>
1886 The IPv6 AAAA record is a parallel to the IPv4 A record,
1887 and, unlike the deprecated A6 record, specifies the entire
1888 IPv6 address in a single record. For example,
1890 <pre class="programlisting">
1891 $ORIGIN example.com.
1892 host 3600 IN AAAA 2001:db8::1
1895 Use of IPv4-in-IPv6 mapped addresses is not recommended.
1896 If a host has an IPv4 address, use an A record, not
1897 a AAAA, with <code class="literal">::ffff:192.168.42.1</code> as
1901 <div class="sect2" lang="en">
1902 <div class="titlepage"><div><div><h3 class="title">
1903 <a name="id2571859"></a>Address to Name Lookups Using Nibble Format</h3></div></div></div>
1905 When looking up an address in nibble format, the address
1906 components are simply reversed, just as in IPv4, and
1907 <code class="literal">ip6.arpa.</code> is appended to the
1909 For example, the following would provide reverse name lookup for
1911 <code class="literal">2001:db8::1</code>.
1913 <pre class="programlisting">
1914 $ORIGIN 0.0.0.0.0.0.0.0.8.b.d.0.1.0.0.2.ip6.arpa.
1915 1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0 14400 IN PTR (
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1923 <table width="100%" summary="Navigation footer">
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1932 <td width="40%" align="left" valign="top">Chapter 3. Name Server Configuration </td>
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1934 <td width="40%" align="right" valign="top"> Chapter 5. The <acronym class="acronym">BIND</acronym> 9 Lightweight Resolver</td>
1938 <p style="text-align: center;">BIND 9.9.8-P2 (Extended Support Version)</p>