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| author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-05 18:37:14 +0000 |
|---|---|---|
| committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-05 18:37:14 +0000 |
| commit | ea648e70a989cca190cd7403fe892fd2dcc290b4 (patch) | |
| tree | e2b6b1c647da68b0d4d66082835e256eb30970e8 /doc/arm/Bv9ARM.ch04.html | |
| parent | Initial commit. (diff) | |
| download | bind9-ea648e70a989cca190cd7403fe892fd2dcc290b4.tar.xz bind9-ea648e70a989cca190cd7403fe892fd2dcc290b4.zip | |
Adding upstream version 1:9.11.5.P4+dfsg.upstream/1%9.11.5.P4+dfsgupstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'doc/arm/Bv9ARM.ch04.html')
| -rw-r--r-- | doc/arm/Bv9ARM.ch04.html | 2872 |
1 files changed, 2872 insertions, 0 deletions
diff --git a/doc/arm/Bv9ARM.ch04.html b/doc/arm/Bv9ARM.ch04.html new file mode 100644 index 0000000..1a86226 --- /dev/null +++ b/doc/arm/Bv9ARM.ch04.html @@ -0,0 +1,2872 @@ +<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> +<!-- + - Copyright (C) 2000-2019 Internet Systems Consortium, Inc. ("ISC") + - + - This Source Code Form is subject to the terms of the Mozilla Public + - License, v. 2.0. If a copy of the MPL was not distributed with this + - file, You can obtain one at http://mozilla.org/MPL/2.0/. +--> +<html lang="en"> +<head> +<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> +<title>Chapter 4. Advanced DNS Features</title> +<meta name="generator" content="DocBook XSL Stylesheets V1.78.1"> +<link rel="home" href="Bv9ARM.html" title="BIND 9 Administrator Reference Manual"> +<link rel="up" href="Bv9ARM.html" title="BIND 9 Administrator Reference Manual"> +<link rel="prev" href="Bv9ARM.ch03.html" title="Chapter 3. Name Server Configuration"> +<link rel="next" href="Bv9ARM.ch05.html" title="Chapter 5. The BIND 9 Lightweight Resolver"> +</head> +<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> +<div class="navheader"> +<table width="100%" summary="Navigation header"> +<tr><th colspan="3" align="center">Chapter 4. Advanced DNS Features</th></tr> +<tr> +<td width="20%" align="left"> +<a accesskey="p" href="Bv9ARM.ch03.html">Prev</a> </td> +<th width="60%" align="center"> </th> +<td width="20%" align="right"> <a accesskey="n" href="Bv9ARM.ch05.html">Next</a> +</td> +</tr> +</table> +<hr> +</div> +<div class="chapter"> +<div class="titlepage"><div><div><h1 class="title"> +<a name="Bv9ARM.ch04"></a>Chapter 4. Advanced DNS Features</h1></div></div></div> +<div class="toc"> +<p><b>Table of Contents</b></p> +<dl class="toc"> +<dt><span class="section"><a href="Bv9ARM.ch04.html#notify">Notify</a></span></dt> +<dt><span class="section"><a href="Bv9ARM.ch04.html#dynamic_update">Dynamic Update</a></span></dt> +<dd><dl><dt><span class="section"><a href="Bv9ARM.ch04.html#journal">The journal file</a></span></dt></dl></dd> +<dt><span class="section"><a href="Bv9ARM.ch04.html#incremental_zone_transfers">Incremental Zone Transfers (IXFR)</a></span></dt> +<dt><span class="section"><a href="Bv9ARM.ch04.html#split_dns">Split DNS</a></span></dt> +<dd><dl><dt><span class="section"><a href="Bv9ARM.ch04.html#split_dns_sample">Example split DNS setup</a></span></dt></dl></dd> +<dt><span class="section"><a href="Bv9ARM.ch04.html#tsig">TSIG</a></span></dt> +<dd><dl> +<dt><span class="section"><a href="Bv9ARM.ch04.html#id-1.5.6.5">Generating a Shared Key</a></span></dt> +<dt><span class="section"><a href="Bv9ARM.ch04.html#id-1.5.6.6">Loading A New Key</a></span></dt> +<dt><span class="section"><a href="Bv9ARM.ch04.html#id-1.5.6.7">Instructing the Server to Use a Key</a></span></dt> +<dt><span class="section"><a href="Bv9ARM.ch04.html#id-1.5.6.8">TSIG-Based Access Control</a></span></dt> +<dt><span class="section"><a href="Bv9ARM.ch04.html#id-1.5.6.9">Errors</a></span></dt> +</dl></dd> +<dt><span class="section"><a href="Bv9ARM.ch04.html#tkey">TKEY</a></span></dt> +<dt><span class="section"><a href="Bv9ARM.ch04.html#sig0">SIG(0)</a></span></dt> +<dt><span class="section"><a href="Bv9ARM.ch04.html#DNSSEC">DNSSEC</a></span></dt> +<dd><dl> +<dt><span class="section"><a href="Bv9ARM.ch04.html#dnssec_keys">Generating Keys</a></span></dt> +<dt><span class="section"><a href="Bv9ARM.ch04.html#dnssec_signing">Signing the Zone</a></span></dt> +<dt><span class="section"><a href="Bv9ARM.ch04.html#dnssec_config">Configuring Servers</a></span></dt> +</dl></dd> +<dt><span class="section"><a href="Bv9ARM.ch04.html#dnssec.dynamic.zones">DNSSEC, Dynamic Zones, and Automatic Signing</a></span></dt> +<dd><dl> +<dt><span class="section"><a href="Bv9ARM.ch04.html#id-1.5.10.2">Converting from insecure to secure</a></span></dt> +<dt><span class="section"><a href="Bv9ARM.ch04.html#id-1.5.10.7">Dynamic DNS update method</a></span></dt> +<dt><span class="section"><a href="Bv9ARM.ch04.html#id-1.5.10.15">Fully automatic zone signing</a></span></dt> +<dt><span class="section"><a href="Bv9ARM.ch04.html#id-1.5.10.24">Private-type records</a></span></dt> +<dt><span class="section"><a href="Bv9ARM.ch04.html#id-1.5.10.31">DNSKEY rollovers</a></span></dt> +<dt><span class="section"><a href="Bv9ARM.ch04.html#id-1.5.10.33">Dynamic DNS update method</a></span></dt> +<dt><span class="section"><a href="Bv9ARM.ch04.html#id-1.5.10.38">Automatic key rollovers</a></span></dt> +<dt><span class="section"><a href="Bv9ARM.ch04.html#id-1.5.10.40">NSEC3PARAM rollovers via UPDATE</a></span></dt> +<dt><span class="section"><a href="Bv9ARM.ch04.html#id-1.5.10.42">Converting from NSEC to NSEC3</a></span></dt> +<dt><span class="section"><a href="Bv9ARM.ch04.html#id-1.5.10.44">Converting from NSEC3 to NSEC</a></span></dt> +<dt><span class="section"><a href="Bv9ARM.ch04.html#id-1.5.10.46">Converting from secure to insecure</a></span></dt> +<dt><span class="section"><a href="Bv9ARM.ch04.html#id-1.5.10.50">Periodic re-signing</a></span></dt> +<dt><span class="section"><a href="Bv9ARM.ch04.html#id-1.5.10.52">NSEC3 and OPTOUT</a></span></dt> +</dl></dd> +<dt><span class="section"><a href="Bv9ARM.ch04.html#rfc5011.support">Dynamic Trust Anchor Management</a></span></dt> +<dd><dl> +<dt><span class="section"><a href="Bv9ARM.ch04.html#id-1.5.11.3">Validating Resolver</a></span></dt> +<dt><span class="section"><a href="Bv9ARM.ch04.html#id-1.5.11.4">Authoritative Server</a></span></dt> +</dl></dd> +<dt><span class="section"><a href="Bv9ARM.ch04.html#pkcs11">PKCS#11 (Cryptoki) support</a></span></dt> +<dd><dl> +<dt><span class="section"><a href="Bv9ARM.ch04.html#id-1.5.12.6">Prerequisites</a></span></dt> +<dt><span class="section"><a href="Bv9ARM.ch04.html#id-1.5.12.7">Native PKCS#11</a></span></dt> +<dt><span class="section"><a href="Bv9ARM.ch04.html#id-1.5.12.8">OpenSSL-based PKCS#11</a></span></dt> +<dt><span class="section"><a href="Bv9ARM.ch04.html#id-1.5.12.9">PKCS#11 Tools</a></span></dt> +<dt><span class="section"><a href="Bv9ARM.ch04.html#id-1.5.12.10">Using the HSM</a></span></dt> +<dt><span class="section"><a href="Bv9ARM.ch04.html#id-1.5.12.11">Specifying the engine on the command line</a></span></dt> +<dt><span class="section"><a href="Bv9ARM.ch04.html#id-1.5.12.12">Running named with automatic zone re-signing</a></span></dt> +</dl></dd> +<dt><span class="section"><a href="Bv9ARM.ch04.html#dlz-info">DLZ (Dynamically Loadable Zones)</a></span></dt> +<dd><dl> +<dt><span class="section"><a href="Bv9ARM.ch04.html#id-1.5.13.6">Configuring DLZ</a></span></dt> +<dt><span class="section"><a href="Bv9ARM.ch04.html#id-1.5.13.7">Sample DLZ Driver</a></span></dt> +</dl></dd> +<dt><span class="section"><a href="Bv9ARM.ch04.html#dyndb-info">DynDB (Dynamic Database)</a></span></dt> +<dd><dl> +<dt><span class="section"><a href="Bv9ARM.ch04.html#id-1.5.14.5">Configuring DynDB</a></span></dt> +<dt><span class="section"><a href="Bv9ARM.ch04.html#id-1.5.14.6">Sample DynDB Module</a></span></dt> +</dl></dd> +<dt><span class="section"><a href="Bv9ARM.ch04.html#catz-info">Catalog Zones</a></span></dt> +<dd><dl> +<dt><span class="section"><a href="Bv9ARM.ch04.html#id-1.5.15.4">Principle of Operation</a></span></dt> +<dt><span class="section"><a href="Bv9ARM.ch04.html#id-1.5.15.5">Configuring Catalog Zones</a></span></dt> +<dt><span class="section"><a href="Bv9ARM.ch04.html#id-1.5.15.6">Catalog Zone format</a></span></dt> +</dl></dd> +<dt><span class="section"><a href="Bv9ARM.ch04.html#ipv6">IPv6 Support in <acronym class="acronym">BIND</acronym> 9</a></span></dt> +<dd><dl> +<dt><span class="section"><a href="Bv9ARM.ch04.html#id-1.5.16.6">Address Lookups Using AAAA Records</a></span></dt> +<dt><span class="section"><a href="Bv9ARM.ch04.html#id-1.5.16.7">Address to Name Lookups Using Nibble Format</a></span></dt> +</dl></dd> +</dl> +</div> + + <div class="section"> +<div class="titlepage"><div><div><h2 class="title" style="clear: both"> +<a name="notify"></a>Notify</h2></div></div></div> + <p> + <acronym class="acronym">DNS</acronym> NOTIFY is a mechanism that allows master + servers to notify their slave servers of changes to a zone's data. In + response to a <span class="command"><strong>NOTIFY</strong></span> from a master server, the + slave will check to see that its version of the zone is the + current version and, if not, initiate a zone transfer. + </p> + + <p> + For more information about <acronym class="acronym">DNS</acronym> + <span class="command"><strong>NOTIFY</strong></span>, see the description of the + <span class="command"><strong>notify</strong></span> option in <a class="xref" href="Bv9ARM.ch06.html#boolean_options" title="Boolean Options">the section called “Boolean Options”</a> and + the description of the zone option <span class="command"><strong>also-notify</strong></span> in + <a class="xref" href="Bv9ARM.ch06.html#zone_transfers" title="Zone Transfers">the section called “Zone Transfers”</a>. The <span class="command"><strong>NOTIFY</strong></span> + protocol is specified in RFC 1996. + </p> + + <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"> +<h3 class="title">Note</h3> +<p> + As a slave zone can also be a master to other slaves, <span class="command"><strong>named</strong></span>, + by default, sends <span class="command"><strong>NOTIFY</strong></span> messages for every zone + it loads. Specifying <span class="command"><strong>notify master-only;</strong></span> will + cause <span class="command"><strong>named</strong></span> to only send <span class="command"><strong>NOTIFY</strong></span> for master + zones that it loads. + </p> +</div> + + </div> + + <div class="section"> +<div class="titlepage"><div><div><h2 class="title" style="clear: both"> +<a name="dynamic_update"></a>Dynamic Update</h2></div></div></div> + + <p> + Dynamic Update is a method for adding, replacing or deleting + records in a master server by sending it a special form of DNS + messages. The format and meaning of these messages is specified + in RFC 2136. + </p> + + <p> + Dynamic update is enabled by including an + <span class="command"><strong>allow-update</strong></span> or an <span class="command"><strong>update-policy</strong></span> + clause in the <span class="command"><strong>zone</strong></span> statement. + </p> + + <p> + If the zone's <span class="command"><strong>update-policy</strong></span> is set to + <strong class="userinput"><code>local</code></strong>, updates to the zone + will be permitted for the key <code class="varname">local-ddns</code>, + which will be generated by <span class="command"><strong>named</strong></span> at startup. + See <a class="xref" href="Bv9ARM.ch06.html#dynamic_update_policies" title="Dynamic Update Policies">the section called “Dynamic Update Policies”</a> for more details. + </p> + + <p> + Dynamic updates using Kerberos signed requests can be made + using the TKEY/GSS protocol by setting either the + <span class="command"><strong>tkey-gssapi-keytab</strong></span> option, or alternatively + by setting both the <span class="command"><strong>tkey-gssapi-credential</strong></span> + and <span class="command"><strong>tkey-domain</strong></span> options. Once enabled, + Kerberos signed requests will be matched against the update + policies for the zone, using the Kerberos principal as the + signer for the request. + </p> + + <p> + Updating of secure zones (zones using DNSSEC) follows RFC + 3007: RRSIG, NSEC and NSEC3 records affected by updates are + automatically regenerated by the server using an online + zone key. Update authorization is based on transaction + signatures and an explicit server policy. + </p> + + <div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="journal"></a>The journal file</h3></div></div></div> + + <p> + All changes made to a zone using dynamic update are stored + in the zone's journal file. This file is automatically created + by the server when the first dynamic update takes place. + The name of the journal file is formed by appending the extension + <code class="filename">.jnl</code> to the name of the + corresponding zone + file unless specifically overridden. The journal file is in a + binary format and should not be edited manually. + </p> + + <p> + The server will also occasionally write ("dump") + the complete contents of the updated zone to its zone file. + This is not done immediately after + each dynamic update, because that would be too slow when a large + zone is updated frequently. Instead, the dump is delayed by + up to 15 minutes, allowing additional updates to take place. + During the dump process, transient files will be created + with the extensions <code class="filename">.jnw</code> and + <code class="filename">.jbk</code>; under ordinary circumstances, these + will be removed when the dump is complete, and can be safely + ignored. + </p> + + <p> + When a server is restarted after a shutdown or crash, it will replay + the journal file to incorporate into the zone any updates that + took + place after the last zone dump. + </p> + + <p> + Changes that result from incoming incremental zone transfers are + also + journalled in a similar way. + </p> + + <p> + The zone files of dynamic zones cannot normally be edited by + hand because they are not guaranteed to contain the most recent + dynamic changes — those are only in the journal file. + The only way to ensure that the zone file of a dynamic zone + is up to date is to run <span class="command"><strong>rndc stop</strong></span>. + </p> + + <p> + If you have to make changes to a dynamic zone + manually, the following procedure will work: + Disable dynamic updates to the zone using + <span class="command"><strong>rndc freeze <em class="replaceable"><code>zone</code></em></strong></span>. + This will update the zone's master file with the changes + stored in its <code class="filename">.jnl</code> file. + Edit the zone file. Run + <span class="command"><strong>rndc thaw <em class="replaceable"><code>zone</code></em></strong></span> + to reload the changed zone and re-enable dynamic updates. + </p> + + <p> + <span class="command"><strong>rndc sync <em class="replaceable"><code>zone</code></em></strong></span> + will update the zone file with changes from the journal file + without stopping dynamic updates; this may be useful for viewing + the current zone state. To remove the <code class="filename">.jnl</code> + file after updating the zone file, use + <span class="command"><strong>rndc sync -clean</strong></span>. + </p> + + </div> + + </div> + + <div class="section"> +<div class="titlepage"><div><div><h2 class="title" style="clear: both"> +<a name="incremental_zone_transfers"></a>Incremental Zone Transfers (IXFR)</h2></div></div></div> + + <p> + The incremental zone transfer (IXFR) protocol is a way for + slave servers to transfer only changed data, instead of having to + transfer the entire zone. The IXFR protocol is specified in RFC + 1995. See <a class="xref" href="Bv9ARM.ch11.html#proposed_standards" title="Proposed Standards">Proposed Standards</a>. + </p> + + <p> + When acting as a master, <acronym class="acronym">BIND</acronym> 9 + supports IXFR for those zones + where the necessary change history information is available. These + include master zones maintained by dynamic update and slave zones + whose data was obtained by IXFR. For manually maintained master + zones, and for slave zones obtained by performing a full zone + transfer (AXFR), IXFR is supported only if the option + <span class="command"><strong>ixfr-from-differences</strong></span> is set + to <strong class="userinput"><code>yes</code></strong>. + </p> + + <p> + When acting as a slave, <acronym class="acronym">BIND</acronym> 9 will + attempt to use IXFR unless + it is explicitly disabled. For more information about disabling + IXFR, see the description of the <span class="command"><strong>request-ixfr</strong></span> clause + of the <span class="command"><strong>server</strong></span> statement. + </p> + </div> + + <div class="section"> +<div class="titlepage"><div><div><h2 class="title" style="clear: both"> +<a name="split_dns"></a>Split DNS</h2></div></div></div> + + <p> + Setting up different views, or visibility, of the DNS space to + internal and external resolvers is usually referred to as a + <span class="emphasis"><em>Split DNS</em></span> setup. There are several + reasons an organization would want to set up its DNS this way. + </p> + <p> + One common reason for setting up a DNS system this way is + to hide "internal" DNS information from "external" clients on the + Internet. There is some debate as to whether or not this is actually + useful. + Internal DNS information leaks out in many ways (via email headers, + for example) and most savvy "attackers" can find the information + they need using other means. + However, since listing addresses of internal servers that + external clients cannot possibly reach can result in + connection delays and other annoyances, an organization may + choose to use a Split DNS to present a consistent view of itself + to the outside world. + </p> + <p> + Another common reason for setting up a Split DNS system is + to allow internal networks that are behind filters or in RFC 1918 + space (reserved IP space, as documented in RFC 1918) to resolve DNS + on the Internet. Split DNS can also be used to allow mail from outside + back in to the internal network. + </p> + <div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="split_dns_sample"></a>Example split DNS setup</h3></div></div></div> + <p> + Let's say a company named <span class="emphasis"><em>Example, Inc.</em></span> + (<code class="literal">example.com</code>) + has several corporate sites that have an internal network with + reserved + Internet Protocol (IP) space and an external demilitarized zone (DMZ), + or "outside" section of a network, that is available to the public. + </p> + <p> + <span class="emphasis"><em>Example, Inc.</em></span> wants its internal clients + to be able to resolve external hostnames and to exchange mail with + people on the outside. The company also wants its internal resolvers + to have access to certain internal-only zones that are not available + at all outside of the internal network. + </p> + <p> + In order to accomplish this, the company will set up two sets + of name servers. One set will be on the inside network (in the + reserved + IP space) and the other set will be on bastion hosts, which are + "proxy" + hosts that can talk to both sides of its network, in the DMZ. + </p> + <p> + The internal servers will be configured to forward all queries, + except queries for <code class="filename">site1.internal</code>, <code class="filename">site2.internal</code>, <code class="filename">site1.example.com</code>, + and <code class="filename">site2.example.com</code>, to the servers + in the + DMZ. These internal servers will have complete sets of information + for <code class="filename">site1.example.com</code>, <code class="filename">site2.example.com</code>, <code class="filename">site1.internal</code>, + and <code class="filename">site2.internal</code>. + </p> + <p> + To protect the <code class="filename">site1.internal</code> and <code class="filename">site2.internal</code> domains, + the internal name servers must be configured to disallow all queries + to these domains from any external hosts, including the bastion + hosts. + </p> + <p> + The external servers, which are on the bastion hosts, will + be configured to serve the "public" version of the <code class="filename">site1</code> and <code class="filename">site2.example.com</code> zones. + This could include things such as the host records for public servers + (<code class="filename">www.example.com</code> and <code class="filename">ftp.example.com</code>), + and mail exchange (MX) records (<code class="filename">a.mx.example.com</code> and <code class="filename">b.mx.example.com</code>). + </p> + <p> + In addition, the public <code class="filename">site1</code> and <code class="filename">site2.example.com</code> zones + should have special MX records that contain wildcard (`*') records + pointing to the bastion hosts. This is needed because external mail + servers do not have any other way of looking up how to deliver mail + to those internal hosts. With the wildcard records, the mail will + be delivered to the bastion host, which can then forward it on to + internal hosts. + </p> + <p> + Here's an example of a wildcard MX record: + </p> + <pre class="programlisting">* IN MX 10 external1.example.com.</pre> + <p> + Now that they accept mail on behalf of anything in the internal + network, the bastion hosts will need to know how to deliver mail + to internal hosts. In order for this to work properly, the resolvers + on + the bastion hosts will need to be configured to point to the internal + name servers for DNS resolution. + </p> + <p> + Queries for internal hostnames will be answered by the internal + servers, and queries for external hostnames will be forwarded back + out to the DNS servers on the bastion hosts. + </p> + <p> + In order for all this to work properly, internal clients will + need to be configured to query <span class="emphasis"><em>only</em></span> the internal + name servers for DNS queries. This could also be enforced via + selective + filtering on the network. + </p> + <p> + If everything has been set properly, <span class="emphasis"><em>Example, Inc.</em></span>'s + internal clients will now be able to: + </p> + <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> +<li class="listitem"> + + Look up any hostnames in the <code class="literal">site1</code> + and + <code class="literal">site2.example.com</code> zones. + + </li> +<li class="listitem"> + + Look up any hostnames in the <code class="literal">site1.internal</code> and + <code class="literal">site2.internal</code> domains. + + </li> +<li class="listitem"> + Look up any hostnames on the Internet. + </li> +<li class="listitem"> + Exchange mail with both internal and external people. + </li> +</ul></div> + <p> + Hosts on the Internet will be able to: + </p> + <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> +<li class="listitem"> + + Look up any hostnames in the <code class="literal">site1</code> + and + <code class="literal">site2.example.com</code> zones. + + </li> +<li class="listitem"> + + Exchange mail with anyone in the <code class="literal">site1</code> and + <code class="literal">site2.example.com</code> zones. + + </li> +</ul></div> + + <p> + Here is an example configuration for the setup we just + described above. Note that this is only configuration information; + for information on how to configure your zone files, see <a class="xref" href="Bv9ARM.ch03.html#sample_configuration" title="Sample Configurations">the section called “Sample Configurations”</a>. + </p> + + <p> + Internal DNS server config: + </p> + +<pre class="programlisting"> + +acl internals { 172.16.72.0/24; 192.168.1.0/24; }; + +acl externals { <code class="varname">bastion-ips-go-here</code>; }; + +options { + ... + ... + forward only; + // forward to external servers + forwarders { + <code class="varname">bastion-ips-go-here</code>; + }; + // sample allow-transfer (no one) + allow-transfer { none; }; + // restrict query access + allow-query { internals; externals; }; + // restrict recursion + allow-recursion { internals; }; + ... + ... +}; + +// sample master zone +zone "site1.example.com" { + type master; + file "m/site1.example.com"; + // do normal iterative resolution (do not forward) + forwarders { }; + allow-query { internals; externals; }; + allow-transfer { internals; }; +}; + +// sample slave zone +zone "site2.example.com" { + type slave; + file "s/site2.example.com"; + masters { 172.16.72.3; }; + forwarders { }; + allow-query { internals; externals; }; + allow-transfer { internals; }; +}; + +zone "site1.internal" { + type master; + file "m/site1.internal"; + forwarders { }; + allow-query { internals; }; + allow-transfer { internals; } +}; + +zone "site2.internal" { + type slave; + file "s/site2.internal"; + masters { 172.16.72.3; }; + forwarders { }; + allow-query { internals }; + allow-transfer { internals; } +}; +</pre> + + <p> + External (bastion host) DNS server config: + </p> + +<pre class="programlisting"> +acl internals { 172.16.72.0/24; 192.168.1.0/24; }; + +acl externals { bastion-ips-go-here; }; + +options { + ... + ... + // sample allow-transfer (no one) + allow-transfer { none; }; + // default query access + allow-query { any; }; + // restrict cache access + allow-query-cache { internals; externals; }; + // restrict recursion + allow-recursion { internals; externals; }; + ... + ... +}; + +// sample slave zone +zone "site1.example.com" { + type master; + file "m/site1.foo.com"; + allow-transfer { internals; externals; }; +}; + +zone "site2.example.com" { + type slave; + file "s/site2.foo.com"; + masters { another_bastion_host_maybe; }; + allow-transfer { internals; externals; } +}; +</pre> + + <p> + In the <code class="filename">resolv.conf</code> (or equivalent) on + the bastion host(s): + </p> + +<pre class="programlisting"> +search ... +nameserver 172.16.72.2 +nameserver 172.16.72.3 +nameserver 172.16.72.4 +</pre> + + </div> + </div> + <div class="section"> +<div class="titlepage"><div><div><h2 class="title" style="clear: both"> +<a name="tsig"></a>TSIG</h2></div></div></div> + + <p> + TSIG (Transaction SIGnatures) is a mechanism for authenticating DNS + messages, originally specified in RFC 2845. It allows DNS messages + to be cryptographically signed using a shared secret. TSIG can + be used in any DNS transaction, as a way to restrict access to + certain server functions (e.g., recursive queries) to authorized + clients when IP-based access control is insufficient or needs to + be overridden, or as a way to ensure message authenticity when it + is critical to the integrity of the server, such as with dynamic + UPDATE messages or zone transfers from a master to a slave server. + </p> + <p> + This is a guide to setting up TSIG in <acronym class="acronym">BIND</acronym>. + It describes the configuration syntax and the process of creating + TSIG keys. + </p> + <p> + <span class="command"><strong>named</strong></span> supports TSIG for server-to-server + communication, and some of the tools included with + <acronym class="acronym">BIND</acronym> support it for sending messages to + <span class="command"><strong>named</strong></span>: + </p> +<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> +<li class="listitem"> + <a class="xref" href="man.nsupdate.html" title="nsupdate"><span class="refentrytitle"><span class="application">nsupdate</span></span>(1)</a> supports TSIG via the + <code class="option">-k</code>, <code class="option">-l</code> and + <code class="option">-y</code> command line options, or via + the <span class="command"><strong>key</strong></span> command when running + interactively. + </li> +<li class="listitem"> + <a class="xref" href="man.dig.html" title="dig"><span class="refentrytitle">dig</span>(1)</a> supports TSIG via the + <code class="option">-k</code> and <code class="option">-y</code> command + line options. + </li> +</ul></div> +<p> + </p> + + <div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="id-1.5.6.5"></a>Generating a Shared Key</h3></div></div></div> + <p> + TSIG keys can be generated using the <span class="command"><strong>tsig-keygen</strong></span> + command; the output of the command is a <span class="command"><strong>key</strong></span> directive + suitable for inclusion in <code class="filename">named.conf</code>. The + key name, algorithm and size can be specified by command line parameters; + the defaults are "tsig-key", HMAC-SHA256, and 256 bits, respectively. + </p> + <p> + Any string which is a valid DNS name can be used as a key name. + For example, a key to be shared between servers called + <span class="emphasis"><em>host1</em></span> and <span class="emphasis"><em>host2</em></span> could + be called "host1-host2.", and this key could be generated using: + </p> +<pre class="programlisting"> + $ tsig-keygen host1-host2. > host1-host2.key +</pre> + <p> + This key may then be copied to both hosts. The key name and secret + must be identical on both hosts. + (Note: copying a shared secret from one server to another is beyond + the scope of the DNS. A secure transport mechanism should be used: + secure FTP, SSL, ssh, telephone, encrypted email, etc.) + </p> + <p> + <span class="command"><strong>tsig-keygen</strong></span> can also be run as + <span class="command"><strong>ddns-confgen</strong></span>, in which case its output includes + additional configuration text for setting up dynamic DNS in + <span class="command"><strong>named</strong></span>. See <a class="xref" href="man.ddns-confgen.html" title="ddns-confgen"><span class="refentrytitle"><span class="application">ddns-confgen</span></span>(8)</a> + for details. + </p> + </div> + + <div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="id-1.5.6.6"></a>Loading A New Key</h3></div></div></div> + <p> + For a key shared between servers called + <span class="emphasis"><em>host1</em></span> and <span class="emphasis"><em>host2</em></span>, + the following could be added to each server's + <code class="filename">named.conf</code> file: + </p> +<pre class="programlisting"> +key "host1-host2." { + algorithm hmac-sha256; + secret "DAopyf1mhCbFVZw7pgmNPBoLUq8wEUT7UuPoLENP2HY="; +}; +</pre> + <p> + (This is the same key generated above using + <span class="command"><strong>tsig-keygen</strong></span>.) + </p> + <p> + Since this text contains a secret, it + is recommended that either <code class="filename">named.conf</code> not be + world-readable, or that the <span class="command"><strong>key</strong></span> directive + be stored in a file which is not world-readable, and which is + included in <code class="filename">named.conf</code> via the + <span class="command"><strong>include</strong></span> directive. + </p> + <p> + Once a key has been added to <code class="filename">named.conf</code> and the + server has been restarted or reconfigured, the server can recognize + the key. If the server receives a message signed by the + key, it will be able to verify the signature. If the signature + is valid, the response will be signed using the same key. + </p> + <p> + TSIG keys that are known to a server can be listed using the + command <span class="command"><strong>rndc tsig-list</strong></span>. + </p> + </div> + + <div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="id-1.5.6.7"></a>Instructing the Server to Use a Key</h3></div></div></div> + <p> + A server sending a request to another server must be told whether + to use a key, and if so, which key to use. + </p> + <p> + For example, a key may be specified for each server in the + <span class="command"><strong>masters</strong></span> statement in the definition of a + slave zone; in this case, all SOA QUERY messages, NOTIFY + messages, and zone transfer requests (AXFR or IXFR) will be + signed using the specified key. Keys may also be specified + in the <span class="command"><strong>also-notify</strong></span> statement of a master + or slave zone, causing NOTIFY messages to be signed using + the specified key. + </p> + <p> + Keys can also be specified in a <span class="command"><strong>server</strong></span> + directive. Adding the following on <span class="emphasis"><em>host1</em></span>, + if the IP address of <span class="emphasis"><em>host2</em></span> is 10.1.2.3, would + cause <span class="emphasis"><em>all</em></span> requests from <span class="emphasis"><em>host1</em></span> + to <span class="emphasis"><em>host2</em></span>, including normal DNS queries, to be + signed using the <span class="command"><strong>host1-host2.</strong></span> key: + </p> +<pre class="programlisting"> +server 10.1.2.3 { + keys { host1-host2. ;}; +}; +</pre> + <p> + Multiple keys may be present in the <span class="command"><strong>keys</strong></span> + statement, but only the first one is used. As this directive does + not contain secrets, it can be used in a world-readable file. + </p> + <p> + Requests sent by <span class="emphasis"><em>host2</em></span> to <span class="emphasis"><em>host1</em></span> + would <span class="emphasis"><em>not</em></span> be signed, unless a similar + <span class="command"><strong>server</strong></span> directive were in <span class="emphasis"><em>host2</em></span>'s + configuration file. + </p> + <p> + Whenever any server sends a TSIG-signed DNS request, it will expect + the response to be signed with the same key. If a response is not + signed, or if the signature is not valid, the response will be + rejected. + </p> + </div> + + <div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="id-1.5.6.8"></a>TSIG-Based Access Control</h3></div></div></div> + <p> + TSIG keys may be specified in ACL definitions and ACL directives + such as <span class="command"><strong>allow-query</strong></span>, <span class="command"><strong>allow-transfer</strong></span> + and <span class="command"><strong>allow-update</strong></span>. + The above key would be denoted in an ACL element as + <span class="command"><strong>key host1-host2.</strong></span> + </p> + <p> + An example of an <span class="command"><strong>allow-update</strong></span> directive using + a TSIG key: + </p> +<pre class="programlisting"> +allow-update { !{ !localnets; any; }; key host1-host2. ;}; +</pre> + <p> + This allows dynamic updates to succeed only if the UPDATE + request comes from an address in <span class="command"><strong>localnets</strong></span>, + <span class="emphasis"><em>and</em></span> if it is signed using the + <span class="command"><strong>host1-host2.</strong></span> key. + </p> + <p> + See <a class="xref" href="Bv9ARM.ch06.html#dynamic_update_policies" title="Dynamic Update Policies">the section called “Dynamic Update Policies”</a> for a discussion of + the more flexible <span class="command"><strong>update-policy</strong></span> statement. + </p> + </div> + + <div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="id-1.5.6.9"></a>Errors</h3></div></div></div> + <p> + Processing of TSIG-signed messages can result in several errors: + </p> +<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> +<li class="listitem"> + If a TSIG-aware server receives a message signed by an + unknown key, the response will be unsigned, with the TSIG + extended error code set to BADKEY. + </li> +<li class="listitem"> + If a TSIG-aware server receives a message from a known key + but with an invalid signature, the response will be unsigned, + with the TSIG extended error code set to BADSIG. + </li> +<li class="listitem"> + If a TSIG-aware server receives a message with a time + outside of the allowed range, the response will be signed, with + the TSIG extended error code set to BADTIME, and the time values + will be adjusted so that the response can be successfully + verified. + </li> +</ul></div> +<p> + In all of the above cases, the server will return a response code + of NOTAUTH (not authenticated). + </p> + </div> + </div> + + <div class="section"> +<div class="titlepage"><div><div><h2 class="title" style="clear: both"> +<a name="tkey"></a>TKEY</h2></div></div></div> + + <p> + TKEY (Transaction KEY) is a mechanism for automatically negotiating + a shared secret between two hosts, originally specified in RFC 2930. + </p> + <p> + There are several TKEY "modes" that specify how a key is to be + generated or assigned. <acronym class="acronym">BIND</acronym> 9 implements only + one of these modes: Diffie-Hellman key exchange. Both hosts are + required to have a KEY record with algorithm DH (though this + record is not required to be present in a zone). + </p> + <p> + The TKEY process is initiated by a client or server by sending + a query of type TKEY to a TKEY-aware server. The query must include + an appropriate KEY record in the additional section, and + must be signed using either TSIG or SIG(0) with a previously + established key. The server's response, if successful, will + contain a TKEY record in its answer section. After this transaction, + both participants will have enough information to calculate a + shared secret using Diffie-Hellman key exchange. The shared secret + can then be used by to sign subsequent transactions between the + two servers. + </p> + <p> + TSIG keys known by the server, including TKEY-negotiated keys, can + be listed using <span class="command"><strong>rndc tsig-list</strong></span>. + </p> + <p> + TKEY-negotiated keys can be deleted from a server using + <span class="command"><strong>rndc tsig-delete</strong></span>. This can also be done via + the TKEY protocol itself, by sending an authenticated TKEY query + specifying the "key deletion" mode. + </p> + + </div> + <div class="section"> +<div class="titlepage"><div><div><h2 class="title" style="clear: both"> +<a name="sig0"></a>SIG(0)</h2></div></div></div> + + <p> + <acronym class="acronym">BIND</acronym> partially supports DNSSEC SIG(0) + transaction signatures as specified in RFC 2535 and RFC 2931. + SIG(0) uses public/private keys to authenticate messages. Access control + is performed in the same manner as TSIG keys; privileges can be + granted or denied in ACL directives based on the key name. + </p> + <p> + When a SIG(0) signed message is received, it will only be + verified if the key is known and trusted by the server. The + server will not attempt to recursively fetch or validate the + key. + </p> + <p> + SIG(0) signing of multiple-message TCP streams is not supported. + </p> + <p> + The only tool shipped with <acronym class="acronym">BIND</acronym> 9 that + generates SIG(0) signed messages is <span class="command"><strong>nsupdate</strong></span>. + </p> + </div> + + <div class="section"> +<div class="titlepage"><div><div><h2 class="title" style="clear: both"> +<a name="DNSSEC"></a>DNSSEC</h2></div></div></div> + <p> + Cryptographic authentication of DNS information is possible + through the DNS Security (<span class="emphasis"><em>DNSSEC-bis</em></span>) extensions, + defined in RFC 4033, RFC 4034, and RFC 4035. + This section describes the creation and use of DNSSEC signed zones. + </p> + + <p> + In order to set up a DNSSEC secure zone, there are a series + of steps which must be followed. <acronym class="acronym">BIND</acronym> + 9 ships + with several tools + that are used in this process, which are explained in more detail + below. In all cases, the <code class="option">-h</code> option prints a + full list of parameters. Note that the DNSSEC tools require the + keyset files to be in the working directory or the + directory specified by the <code class="option">-d</code> option, and + that the tools shipped with BIND 9.2.x and earlier are not compatible + with the current ones. + </p> + + <p> + There must also be communication with the administrators of + the parent and/or child zone to transmit keys. A zone's security + status must be indicated by the parent zone for a DNSSEC capable + resolver to trust its data. This is done through the presence + or absence of a <code class="literal">DS</code> record at the + delegation + point. + </p> + + <p> + For other servers to trust data in this zone, they must + either be statically configured with this zone's zone key or the + zone key of another zone above this one in the DNS tree. + </p> + + <div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="dnssec_keys"></a>Generating Keys</h3></div></div></div> + + <p> + The <span class="command"><strong>dnssec-keygen</strong></span> program is used to + generate keys. + </p> + + <p> + A secure zone must contain one or more zone keys. The + zone keys will sign all other records in the zone, as well as + the zone keys of any secure delegated zones. Zone keys must + have the same name as the zone, a name type of + <span class="command"><strong>ZONE</strong></span>, and must be usable for + authentication. + It is recommended that zone keys use a cryptographic algorithm + designated as "mandatory to implement" by the IETF; currently + the only one is RSASHA1. + </p> + + <p> + The following command will generate a 768-bit RSASHA1 key for + the <code class="filename">child.example</code> zone: + </p> + + <p> + <strong class="userinput"><code>dnssec-keygen -a RSASHA1 -b 768 -n ZONE child.example.</code></strong> + </p> + + <p> + Two output files will be produced: + <code class="filename">Kchild.example.+005+12345.key</code> and + <code class="filename">Kchild.example.+005+12345.private</code> + (where + 12345 is an example of a key tag). The key filenames contain + the key name (<code class="filename">child.example.</code>), + algorithm (3 + is DSA, 1 is RSAMD5, 5 is RSASHA1, etc.), and the key tag (12345 in + this case). + The private key (in the <code class="filename">.private</code> + file) is + used to generate signatures, and the public key (in the + <code class="filename">.key</code> file) is used for signature + verification. + </p> + + <p> + To generate another key with the same properties (but with + a different key tag), repeat the above command. + </p> + + <p> + The <span class="command"><strong>dnssec-keyfromlabel</strong></span> program is used + to get a key pair from a crypto hardware and build the key + files. Its usage is similar to <span class="command"><strong>dnssec-keygen</strong></span>. + </p> + + <p> + The public keys should be inserted into the zone file by + including the <code class="filename">.key</code> files using + <span class="command"><strong>$INCLUDE</strong></span> statements. + </p> + + </div> + <div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="dnssec_signing"></a>Signing the Zone</h3></div></div></div> + + <p> + The <span class="command"><strong>dnssec-signzone</strong></span> program is used + to sign a zone. + </p> + + <p> + Any <code class="filename">keyset</code> files corresponding to + secure subzones should be present. The zone signer will + generate <code class="literal">NSEC</code>, <code class="literal">NSEC3</code> + and <code class="literal">RRSIG</code> records for the zone, as + well as <code class="literal">DS</code> for the child zones if + <code class="literal">'-g'</code> is specified. If <code class="literal">'-g'</code> + is not specified, then DS RRsets for the secure child + zones need to be added manually. + </p> + + <p> + The following command signs the zone, assuming it is in a + file called <code class="filename">zone.child.example</code>. By + default, all zone keys which have an available private key are + used to generate signatures. + </p> + + <p> + <strong class="userinput"><code>dnssec-signzone -o child.example zone.child.example</code></strong> + </p> + + <p> + One output file is produced: + <code class="filename">zone.child.example.signed</code>. This + file + should be referenced by <code class="filename">named.conf</code> + as the + input file for the zone. + </p> + + <p><span class="command"><strong>dnssec-signzone</strong></span> + will also produce a keyset and dsset files and optionally a + dlvset file. These are used to provide the parent zone + administrators with the <code class="literal">DNSKEYs</code> (or their + corresponding <code class="literal">DS</code> records) that are the + secure entry point to the zone. + </p> + + </div> + + <div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="dnssec_config"></a>Configuring Servers</h3></div></div></div> + + <p> + To enable <span class="command"><strong>named</strong></span> to respond appropriately + to DNS requests from DNSSEC aware clients, + <span class="command"><strong>dnssec-enable</strong></span> must be set to yes. + (This is the default setting.) + </p> + + <p> + To enable <span class="command"><strong>named</strong></span> to validate answers from + other servers, the <span class="command"><strong>dnssec-enable</strong></span> option + must be set to <strong class="userinput"><code>yes</code></strong>, and the + <span class="command"><strong>dnssec-validation</strong></span> options must be set to + <strong class="userinput"><code>yes</code></strong> or <strong class="userinput"><code>auto</code></strong>. + </p> + + <p> + If <span class="command"><strong>dnssec-validation</strong></span> is set to + <strong class="userinput"><code>auto</code></strong>, then a default + trust anchor for the DNS root zone will be used. + If it is set to <strong class="userinput"><code>yes</code></strong>, however, + then at least one trust anchor must be configured + with a <span class="command"><strong>trusted-keys</strong></span> or + <span class="command"><strong>managed-keys</strong></span> statement in + <code class="filename">named.conf</code>, or DNSSEC validation + will not occur. The default setting is + <strong class="userinput"><code>yes</code></strong>. + </p> + + <p> + <span class="command"><strong>trusted-keys</strong></span> are copies of DNSKEY RRs + for zones that are used to form the first link in the + cryptographic chain of trust. All keys listed in + <span class="command"><strong>trusted-keys</strong></span> (and corresponding zones) + are deemed to exist and only the listed keys will be used + to validated the DNSKEY RRset that they are from. + </p> + + <p> + <span class="command"><strong>managed-keys</strong></span> are trusted keys which are + automatically kept up to date via RFC 5011 trust anchor + maintenance. + </p> + + <p> + <span class="command"><strong>trusted-keys</strong></span> and + <span class="command"><strong>managed-keys</strong></span> are described in more detail + later in this document. + </p> + + <p> + Unlike <acronym class="acronym">BIND</acronym> 8, <acronym class="acronym">BIND</acronym> + 9 does not verify signatures on load, so zone keys for + authoritative zones do not need to be specified in the + configuration file. + </p> + + <p> + After DNSSEC gets established, a typical DNSSEC configuration + will look something like the following. It has one or + more public keys for the root. This allows answers from + outside the organization to be validated. It will also + have several keys for parts of the namespace the organization + controls. These are here to ensure that <span class="command"><strong>named</strong></span> + is immune to compromises in the DNSSEC components of the security + of parent zones. + </p> + +<pre class="programlisting"> +managed-keys { + /* Root Key */ + "." initial-key 257 3 3 "BNY4wrWM1nCfJ+CXd0rVXyYmobt7sEEfK3clRbGaTwS + JxrGkxJWoZu6I7PzJu/E9gx4UC1zGAHlXKdE4zYIpRh + aBKnvcC2U9mZhkdUpd1Vso/HAdjNe8LmMlnzY3zy2Xy + 4klWOADTPzSv9eamj8V18PHGjBLaVtYvk/ln5ZApjYg + hf+6fElrmLkdaz MQ2OCnACR817DF4BBa7UR/beDHyp + 5iWTXWSi6XmoJLbG9Scqc7l70KDqlvXR3M/lUUVRbke + g1IPJSidmK3ZyCllh4XSKbje/45SKucHgnwU5jefMtq + 66gKodQj+MiA21AfUVe7u99WzTLzY3qlxDhxYQQ20FQ + 97S+LKUTpQcq27R7AT3/V5hRQxScINqwcz4jYqZD2fQ + dgxbcDTClU0CRBdiieyLMNzXG3"; +}; + +trusted-keys { + /* Key for our organization's forward zone */ + example.com. 257 3 5 "AwEAAaxPMcR2x0HbQV4WeZB6oEDX+r0QM6 + 5KbhTjrW1ZaARmPhEZZe3Y9ifgEuq7vZ/z + GZUdEGNWy+JZzus0lUptwgjGwhUS1558Hb + 4JKUbbOTcM8pwXlj0EiX3oDFVmjHO444gL + kBOUKUf/mC7HvfwYH/Be22GnClrinKJp1O + g4ywzO9WglMk7jbfW33gUKvirTHr25GL7S + TQUzBb5Usxt8lgnyTUHs1t3JwCY5hKZ6Cq + FxmAVZP20igTixin/1LcrgX/KMEGd/biuv + F4qJCyduieHukuY3H4XMAcR+xia2nIUPvm + /oyWR8BW/hWdzOvnSCThlHf3xiYleDbt/o + 1OTQ09A0="; + + /* Key for our reverse zone. */ + 2.0.192.IN-ADDRPA.NET. 257 3 5 "AQOnS4xn/IgOUpBPJ3bogzwc + xOdNax071L18QqZnQQQAVVr+i + LhGTnNGp3HoWQLUIzKrJVZ3zg + gy3WwNT6kZo6c0tszYqbtvchm + gQC8CzKojM/W16i6MG/eafGU3 + siaOdS0yOI6BgPsw+YZdzlYMa + IJGf4M4dyoKIhzdZyQ2bYQrjy + Q4LB0lC7aOnsMyYKHHYeRvPxj + IQXmdqgOJGq+vsevG06zW+1xg + YJh9rCIfnm1GX/KMgxLPG2vXT + D/RnLX+D3T3UL7HJYHJhAZD5L + 59VvjSPsZJHeDCUyWYrvPZesZ + DIRvhDD52SKvbheeTJUm6Ehkz + ytNN2SN96QRk8j/iI8ib"; +}; + +options { + ... + dnssec-enable yes; + dnssec-validation yes; +}; +</pre> + + <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"> +<h3 class="title">Note</h3> +<p> + None of the keys listed in this example are valid. In particular, + the root key is not valid. + </p> +</div> + + <p> + When DNSSEC validation is enabled and properly configured, + the resolver will reject any answers from signed, secure zones + which fail to validate, and will return SERVFAIL to the client. + </p> + + <p> + Responses may fail to validate for any of several reasons, + including missing, expired, or invalid signatures, a key which + does not match the DS RRset in the parent zone, or an insecure + response from a zone which, according to its parent, should have + been secure. + </p> + + <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"> +<h3 class="title">Note</h3> + <p> + When the validator receives a response from an unsigned zone + that has a signed parent, it must confirm with the parent + that the zone was intentionally left unsigned. It does + this by verifying, via signed and validated NSEC/NSEC3 records, + that the parent zone contains no DS records for the child. + </p> + <p> + If the validator <span class="emphasis"><em>can</em></span> prove that the zone + is insecure, then the response is accepted. However, if it + cannot, then it must assume an insecure response to be a + forgery; it rejects the response and logs an error. + </p> + <p> + The logged error reads "insecurity proof failed" and + "got insecure response; parent indicates it should be secure". + </p> + </div> + </div> + </div> + + <div class="section"> +<div class="titlepage"><div><div><h2 class="title" style="clear: both"> +<a name="dnssec.dynamic.zones"></a>DNSSEC, Dynamic Zones, and Automatic Signing</h2></div></div></div> + + <div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="id-1.5.10.2"></a>Converting from insecure to secure</h3></div></div></div> + + </div> + <p>Changing a zone from insecure to secure can be done in two + ways: using a dynamic DNS update, or the + <span class="command"><strong>auto-dnssec</strong></span> zone option.</p> + <p>For either method, you need to configure + <span class="command"><strong>named</strong></span> so that it can see the + <code class="filename">K*</code> files which contain the public and private + parts of the keys that will be used to sign the zone. These files + will have been generated by + <span class="command"><strong>dnssec-keygen</strong></span>. You can do this by placing them + in the key-directory, as specified in + <code class="filename">named.conf</code>:</p> + <pre class="programlisting"> + zone example.net { + type master; + update-policy local; + file "dynamic/example.net/example.net"; + key-directory "dynamic/example.net"; + }; +</pre> + <p>If one KSK and one ZSK DNSKEY key have been generated, this + configuration will cause all records in the zone to be signed + with the ZSK, and the DNSKEY RRset to be signed with the KSK as + well. An NSEC chain will be generated as part of the initial + signing process.</p> + <div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="id-1.5.10.7"></a>Dynamic DNS update method</h3></div></div></div> + + </div> + <p>To insert the keys via dynamic update:</p> + <pre class="screen"> + % nsupdate + > ttl 3600 + > update add example.net DNSKEY 256 3 7 AwEAAZn17pUF0KpbPA2c7Gz76Vb18v0teKT3EyAGfBfL8eQ8al35zz3Y I1m/SAQBxIqMfLtIwqWPdgthsu36azGQAX8= + > update add example.net DNSKEY 257 3 7 AwEAAd/7odU/64o2LGsifbLtQmtO8dFDtTAZXSX2+X3e/UNlq9IHq3Y0 XtC0Iuawl/qkaKVxXe2lo8Ct+dM6UehyCqk= + > send +</pre> + <p>While the update request will complete almost immediately, + the zone will not be completely signed until + <span class="command"><strong>named</strong></span> has had time to walk the zone and + generate the NSEC and RRSIG records. The NSEC record at the apex + will be added last, to signal that there is a complete NSEC + chain.</p> + <p>If you wish to sign using NSEC3 instead of NSEC, you should + add an NSEC3PARAM record to the initial update request. If you + wish the NSEC3 chain to have the OPTOUT bit set, set it in the + flags field of the NSEC3PARAM record.</p> + <pre class="screen"> + % nsupdate + > ttl 3600 + > update add example.net DNSKEY 256 3 7 AwEAAZn17pUF0KpbPA2c7Gz76Vb18v0teKT3EyAGfBfL8eQ8al35zz3Y I1m/SAQBxIqMfLtIwqWPdgthsu36azGQAX8= + > update add example.net DNSKEY 257 3 7 AwEAAd/7odU/64o2LGsifbLtQmtO8dFDtTAZXSX2+X3e/UNlq9IHq3Y0 XtC0Iuawl/qkaKVxXe2lo8Ct+dM6UehyCqk= + > update add example.net NSEC3PARAM 1 1 100 1234567890 + > send +</pre> + <p>Again, this update request will complete almost + immediately; however, the record won't show up until + <span class="command"><strong>named</strong></span> has had a chance to build/remove the + relevant chain. A private type record will be created to record + the state of the operation (see below for more details), and will + be removed once the operation completes.</p> + <p>While the initial signing and NSEC/NSEC3 chain generation + is happening, other updates are possible as well.</p> + <div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="id-1.5.10.15"></a>Fully automatic zone signing</h3></div></div></div> + + </div> + <p>To enable automatic signing, add the + <span class="command"><strong>auto-dnssec</strong></span> option to the zone statement in + <code class="filename">named.conf</code>. + <span class="command"><strong>auto-dnssec</strong></span> has two possible arguments: + <code class="constant">allow</code> or + <code class="constant">maintain</code>.</p> + <p>With + <span class="command"><strong>auto-dnssec allow</strong></span>, + <span class="command"><strong>named</strong></span> can search the key directory for keys + matching the zone, insert them into the zone, and use them to + sign the zone. It will do so only when it receives an + <span class="command"><strong>rndc sign <zonename></strong></span>.</p> + <p> + + <span class="command"><strong>auto-dnssec maintain</strong></span> includes the above + functionality, but will also automatically adjust the zone's + DNSKEY records on schedule according to the keys' timing metadata. + (See <a class="xref" href="man.dnssec-keygen.html" title="dnssec-keygen"><span class="refentrytitle"><span class="application">dnssec-keygen</span></span>(8)</a> and + <a class="xref" href="man.dnssec-settime.html" title="dnssec-settime"><span class="refentrytitle"><span class="application">dnssec-settime</span></span>(8)</a> for more information.) + </p> + <p> + <span class="command"><strong>named</strong></span> will periodically search the key directory + for keys matching the zone, and if the keys' metadata indicates + that any change should be made the zone, such as adding, removing, + or revoking a key, then that action will be carried out. By default, + the key directory is checked for changes every 60 minutes; this period + can be adjusted with the <code class="option">dnssec-loadkeys-interval</code>, up + to a maximum of 24 hours. The <span class="command"><strong>rndc loadkeys</strong></span> forces + <span class="command"><strong>named</strong></span> to check for key updates immediately. + </p> + <p> + If keys are present in the key directory the first time the zone + is loaded, the zone will be signed immediately, without waiting for an + <span class="command"><strong>rndc sign</strong></span> or <span class="command"><strong>rndc loadkeys</strong></span> + command. (Those commands can still be used when there are unscheduled + key changes, however.) + </p> + <p> + When new keys are added to a zone, the TTL is set to match that + of any existing DNSKEY RRset. If there is no existing DNSKEY RRset, + then the TTL will be set to the TTL specified when the key was + created (using the <span class="command"><strong>dnssec-keygen -L</strong></span> option), if + any, or to the SOA TTL. + </p> + <p> + If you wish the zone to be signed using NSEC3 instead of NSEC, + submit an NSEC3PARAM record via dynamic update prior to the + scheduled publication and activation of the keys. If you wish the + NSEC3 chain to have the OPTOUT bit set, set it in the flags field + of the NSEC3PARAM record. The NSEC3PARAM record will not appear in + the zone immediately, but it will be stored for later reference. When + the zone is signed and the NSEC3 chain is completed, the NSEC3PARAM + record will appear in the zone. + </p> + <p>Using the + <span class="command"><strong>auto-dnssec</strong></span> option requires the zone to be + configured to allow dynamic updates, by adding an + <span class="command"><strong>allow-update</strong></span> or + <span class="command"><strong>update-policy</strong></span> statement to the zone + configuration. If this has not been done, the configuration will + fail.</p> + <div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="id-1.5.10.24"></a>Private-type records</h3></div></div></div> + + </div> + <p>The state of the signing process is signaled by + private-type records (with a default type value of 65534). When + signing is complete, these records will have a nonzero value for + the final octet (for those records which have a nonzero initial + octet).</p> + <p>The private type record format: If the first octet is + non-zero then the record indicates that the zone needs to be + signed with the key matching the record, or that all signatures + that match the record should be removed.</p> + <p> + </p> +<div class="literallayout"><p><br> +<br> + algorithm (octet 1)<br> + key id in network order (octet 2 and 3)<br> + removal flag (octet 4)<br> + complete flag (octet 5)<br> +</p></div> +<p> + </p> + <p>Only records flagged as "complete" can be removed via + dynamic update. Attempts to remove other private type records + will be silently ignored.</p> + <p>If the first octet is zero (this is a reserved algorithm + number that should never appear in a DNSKEY record) then the + record indicates changes to the NSEC3 chains are in progress. The + rest of the record contains an NSEC3PARAM record. The flag field + tells what operation to perform based on the flag bits.</p> + <p> + </p> +<div class="literallayout"><p><br> +<br> + 0x01 OPTOUT<br> + 0x80 CREATE<br> + 0x40 REMOVE<br> + 0x20 NONSEC<br> +</p></div> +<p> + </p> + <div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="id-1.5.10.31"></a>DNSKEY rollovers</h3></div></div></div> + + </div> + <p>As with insecure-to-secure conversions, rolling DNSSEC + keys can be done in two ways: using a dynamic DNS update, or the + <span class="command"><strong>auto-dnssec</strong></span> zone option.</p> + <div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="id-1.5.10.33"></a>Dynamic DNS update method</h3></div></div></div> + + </div> + <p> To perform key rollovers via dynamic update, you need to add + the <code class="filename">K*</code> files for the new keys so that + <span class="command"><strong>named</strong></span> can find them. You can then add the new + DNSKEY RRs via dynamic update. + <span class="command"><strong>named</strong></span> will then cause the zone to be signed + with the new keys. When the signing is complete the private type + records will be updated so that the last octet is non + zero.</p> + <p>If this is for a KSK you need to inform the parent and any + trust anchor repositories of the new KSK.</p> + <p>You should then wait for the maximum TTL in the zone before + removing the old DNSKEY. If it is a KSK that is being updated, + you also need to wait for the DS RRset in the parent to be + updated and its TTL to expire. This ensures that all clients will + be able to verify at least one signature when you remove the old + DNSKEY.</p> + <p>The old DNSKEY can be removed via UPDATE. Take care to + specify the correct key. + <span class="command"><strong>named</strong></span> will clean out any signatures generated + by the old key after the update completes.</p> + <div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="id-1.5.10.38"></a>Automatic key rollovers</h3></div></div></div> + + </div> + <p>When a new key reaches its activation date (as set by + <span class="command"><strong>dnssec-keygen</strong></span> or <span class="command"><strong>dnssec-settime</strong></span>), + if the <span class="command"><strong>auto-dnssec</strong></span> zone option is set to + <code class="constant">maintain</code>, <span class="command"><strong>named</strong></span> will + automatically carry out the key rollover. If the key's algorithm + has not previously been used to sign the zone, then the zone will + be fully signed as quickly as possible. However, if the new key + is replacing an existing key of the same algorithm, then the + zone will be re-signed incrementally, with signatures from the + old key being replaced with signatures from the new key as their + signature validity periods expire. By default, this rollover + completes in 30 days, after which it will be safe to remove the + old key from the DNSKEY RRset.</p> + <div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="id-1.5.10.40"></a>NSEC3PARAM rollovers via UPDATE</h3></div></div></div> + + </div> + <p>Add the new NSEC3PARAM record via dynamic update. When the + new NSEC3 chain has been generated, the NSEC3PARAM flag field + will be zero. At this point you can remove the old NSEC3PARAM + record. The old chain will be removed after the update request + completes.</p> + <div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="id-1.5.10.42"></a>Converting from NSEC to NSEC3</h3></div></div></div> + + </div> + <p>To do this, you just need to add an NSEC3PARAM record. When + the conversion is complete, the NSEC chain will have been removed + and the NSEC3PARAM record will have a zero flag field. The NSEC3 + chain will be generated before the NSEC chain is + destroyed.</p> + <div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="id-1.5.10.44"></a>Converting from NSEC3 to NSEC</h3></div></div></div> + + </div> + <p>To do this, use <span class="command"><strong>nsupdate</strong></span> to + remove all NSEC3PARAM records with a zero flag + field. The NSEC chain will be generated before the NSEC3 chain is + removed.</p> + <div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="id-1.5.10.46"></a>Converting from secure to insecure</h3></div></div></div> + + </div> + <p>To convert a signed zone to unsigned using dynamic DNS, + delete all the DNSKEY records from the zone apex using + <span class="command"><strong>nsupdate</strong></span>. All signatures, NSEC or NSEC3 chains, + and associated NSEC3PARAM records will be removed automatically. + This will take place after the update request completes.</p> + <p> This requires the + <span class="command"><strong>dnssec-secure-to-insecure</strong></span> option to be set to + <strong class="userinput"><code>yes</code></strong> in + <code class="filename">named.conf</code>.</p> + <p>In addition, if the <span class="command"><strong>auto-dnssec maintain</strong></span> + zone statement is used, it should be removed or changed to + <span class="command"><strong>allow</strong></span> instead (or it will re-sign). + </p> + <div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="id-1.5.10.50"></a>Periodic re-signing</h3></div></div></div> + + </div> + <p>In any secure zone which supports dynamic updates, <span class="command"><strong>named</strong></span> + will periodically re-sign RRsets which have not been re-signed as + a result of some update action. The signature lifetimes will be + adjusted so as to spread the re-sign load over time rather than + all at once.</p> + <div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="id-1.5.10.52"></a>NSEC3 and OPTOUT</h3></div></div></div> + + </div> + <p> + <span class="command"><strong>named</strong></span> only supports creating new NSEC3 chains + where all the NSEC3 records in the zone have the same OPTOUT + state. + <span class="command"><strong>named</strong></span> supports UPDATES to zones where the NSEC3 + records in the chain have mixed OPTOUT state. + <span class="command"><strong>named</strong></span> does not support changing the OPTOUT + state of an individual NSEC3 record, the entire chain needs to be + changed if the OPTOUT state of an individual NSEC3 needs to be + changed.</p> +</div> + + <div class="section"> +<div class="titlepage"><div><div><h2 class="title" style="clear: both"> +<a name="rfc5011.support"></a>Dynamic Trust Anchor Management</h2></div></div></div> + + <p> + BIND is able to maintain DNSSEC trust anchors using RFC 5011 key + management. This feature allows <span class="command"><strong>named</strong></span> to keep track + of changes to critical DNSSEC keys without any need for the operator to + make changes to configuration files. + </p> + + <div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="id-1.5.11.3"></a>Validating Resolver</h3></div></div></div> + + + <p>To configure a validating resolver to use RFC 5011 to + maintain a trust anchor, configure the trust anchor using a + <span class="command"><strong>managed-keys</strong></span> statement. Information about + this can be found in + <a class="xref" href="Bv9ARM.ch06.html#managed-keys" title="managed-keys Statement Definition and Usage">the section called “<span class="command"><strong>managed-keys</strong></span> Statement Definition + and Usage”</a>.</p> + + </div> + <div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="id-1.5.11.4"></a>Authoritative Server</h3></div></div></div> + + <p>To set up an authoritative zone for RFC 5011 trust anchor + maintenance, generate two (or more) key signing keys (KSKs) for + the zone. Sign the zone with one of them; this is the "active" + KSK. All KSKs which do not sign the zone are "stand-by" + keys.</p> + <p>Any validating resolver which is configured to use the + active KSK as an RFC 5011-managed trust anchor will take note + of the stand-by KSKs in the zone's DNSKEY RRset, and store them + for future reference. The resolver will recheck the zone + periodically, and after 30 days, if the new key is still there, + then the key will be accepted by the resolver as a valid trust + anchor for the zone. Any time after this 30-day acceptance + timer has completed, the active KSK can be revoked, and the + zone can be "rolled over" to the newly accepted key.</p> + <p>The easiest way to place a stand-by key in a zone is to + use the "smart signing" features of + <span class="command"><strong>dnssec-keygen</strong></span> and + <span class="command"><strong>dnssec-signzone</strong></span>. If a key with a publication + date in the past, but an activation date which is unset or in + the future, " + <span class="command"><strong>dnssec-signzone -S</strong></span>" will include the DNSKEY + record in the zone, but will not sign with it:</p> + <pre class="screen"> +$ <strong class="userinput"><code>dnssec-keygen -K keys -f KSK -P now -A now+2y example.net</code></strong> +$ <strong class="userinput"><code>dnssec-signzone -S -K keys example.net</code></strong> +</pre> + <p>To revoke a key, the new command + <span class="command"><strong>dnssec-revoke</strong></span> has been added. This adds the + REVOKED bit to the key flags and re-generates the + <code class="filename">K*.key</code> and + <code class="filename">K*.private</code> files.</p> + <p>After revoking the active key, the zone must be signed + with both the revoked KSK and the new active KSK. (Smart + signing takes care of this automatically.)</p> + <p>Once a key has been revoked and used to sign the DNSKEY + RRset in which it appears, that key will never again be + accepted as a valid trust anchor by the resolver. However, + validation can proceed using the new active key (which had been + accepted by the resolver when it was a stand-by key).</p> + <p>See RFC 5011 for more details on key rollover + scenarios.</p> + <p>When a key has been revoked, its key ID changes, + increasing by 128, and wrapping around at 65535. So, for + example, the key "<code class="filename">Kexample.com.+005+10000</code>" becomes + "<code class="filename">Kexample.com.+005+10128</code>".</p> + <p>If two keys have IDs exactly 128 apart, and one is + revoked, then the two key IDs will collide, causing several + problems. To prevent this, + <span class="command"><strong>dnssec-keygen</strong></span> will not generate a new key if + another key is present which may collide. This checking will + only occur if the new keys are written to the same directory + which holds all other keys in use for that zone.</p> + <p>Older versions of BIND 9 did not have this precaution. + Exercise caution if using key revocation on keys that were + generated by previous releases, or if using keys stored in + multiple directories or on multiple machines.</p> + <p>It is expected that a future release of BIND 9 will + address this problem in a different way, by storing revoked + keys with their original unrevoked key IDs.</p> + </div> +</div> + + <div class="section"> +<div class="titlepage"><div><div><h2 class="title" style="clear: both"> +<a name="pkcs11"></a>PKCS#11 (Cryptoki) support</h2></div></div></div> + + <p> + PKCS#11 (Public Key Cryptography Standard #11) defines a + platform-independent API for the control of hardware security + modules (HSMs) and other cryptographic support devices. + </p> + <p> + BIND 9 is known to work with three HSMs: The AEP Keyper, which has + been tested with Debian Linux, Solaris x86 and Windows Server 2003; + the Thales nShield, tested with Debian Linux; and the Sun SCA 6000 + cryptographic acceleration board, tested with Solaris x86. In + addition, BIND can be used with all current versions of SoftHSM, + a software-based HSM simulator library produced by the OpenDNSSEC + project. + </p> + <p> + PKCS#11 makes use of a "provider library": a dynamically loadable + library which provides a low-level PKCS#11 interface to drive the HSM + hardware. The PKCS#11 provider library comes from the HSM vendor, and + it is specific to the HSM to be controlled. + </p> + <p> + There are two available mechanisms for PKCS#11 support in BIND 9: + OpenSSL-based PKCS#11 and native PKCS#11. When using the first + mechanism, BIND uses a modified version of OpenSSL, which loads + the provider library and operates the HSM indirectly; any + cryptographic operations not supported by the HSM can be carried + out by OpenSSL instead. The second mechanism enables BIND to bypass + OpenSSL completely; BIND loads the provider library itself, and uses + the PKCS#11 API to drive the HSM directly. + </p> + <div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="id-1.5.12.6"></a>Prerequisites</h3></div></div></div> + + <p> + See the documentation provided by your HSM vendor for + information about installing, initializing, testing and + troubleshooting the HSM. + </p> + </div> + <div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="id-1.5.12.7"></a>Native PKCS#11</h3></div></div></div> + + <p> + Native PKCS#11 mode will only work with an HSM capable of carrying + out <span class="emphasis"><em>every</em></span> cryptographic operation BIND 9 may + need. The HSM's provider library must have a complete implementation + of the PKCS#11 API, so that all these functions are accessible. As of + this writing, only the Thales nShield HSM and SoftHSMv2 can be used + in this fashion. For other HSMs, including the AEP Keyper, Sun SCA + 6000 and older versions of SoftHSM, use OpenSSL-based PKCS#11. + (Note: Eventually, when more HSMs become capable of supporting + native PKCS#11, it is expected that OpenSSL-based PKCS#11 will + be deprecated.) + </p> + <p> + To build BIND with native PKCS#11, configure as follows: + </p> + <pre class="screen"> +$ <strong class="userinput"><code>cd bind9</code></strong> +$ <strong class="userinput"><code>./configure --enable-native-pkcs11 \ + --with-pkcs11=<em class="replaceable"><code>provider-library-path</code></em></code></strong> + </pre> + <p> + This will cause all BIND tools, including <span class="command"><strong>named</strong></span> + and the <span class="command"><strong>dnssec-*</strong></span> and <span class="command"><strong>pkcs11-*</strong></span> + tools, to use the PKCS#11 provider library specified in + <em class="replaceable"><code>provider-library-path</code></em> for cryptography. + (The provider library path can be overridden using the + <code class="option">-E</code> in <span class="command"><strong>named</strong></span> and the + <span class="command"><strong>dnssec-*</strong></span> tools, or the <code class="option">-m</code> in + the <span class="command"><strong>pkcs11-*</strong></span> tools.) + </p> + <div class="section"> +<div class="titlepage"><div><div><h4 class="title"> +<a name="id-1.5.12.7.6"></a>Building SoftHSMv2</h4></div></div></div> + + <p> + SoftHSMv2, the latest development version of SoftHSM, is available + from + <a class="link" href="https://github.com/opendnssec/SoftHSMv2" target="_top"> + https://github.com/opendnssec/SoftHSMv2 + </a>. + It is a software library developed by the OpenDNSSEC project + (<a class="link" href="http://www.opendnssec.org" target="_top"> + http://www.opendnssec.org + </a>) + which provides a PKCS#11 interface to a virtual HSM, implemented in + the form of a SQLite3 database on the local filesystem. It provides + less security than a true HSM, but it allows you to experiment with + native PKCS#11 when an HSM is not available. SoftHSMv2 can be + configured to use either OpenSSL or the Botan library to perform + cryptographic functions, but when using it for native PKCS#11 in + BIND, OpenSSL is required. + </p> + <p> + By default, the SoftHSMv2 configuration file is + <em class="replaceable"><code>prefix</code></em>/etc/softhsm2.conf (where + <em class="replaceable"><code>prefix</code></em> is configured at compile time). + This location can be overridden by the SOFTHSM2_CONF environment + variable. The SoftHSMv2 cryptographic store must be installed and + initialized before using it with BIND. + </p> + <pre class="screen"> +$ <strong class="userinput"><code> cd SoftHSMv2 </code></strong> +$ <strong class="userinput"><code> configure --with-crypto-backend=openssl --prefix=/opt/pkcs11/usr --enable-gost </code></strong> +$ <strong class="userinput"><code> make </code></strong> +$ <strong class="userinput"><code> make install </code></strong> +$ <strong class="userinput"><code> /opt/pkcs11/usr/bin/softhsm-util --init-token 0 --slot 0 --label softhsmv2 </code></strong> + </pre> + </div> + </div> + <div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="id-1.5.12.8"></a>OpenSSL-based PKCS#11</h3></div></div></div> + + <p> + OpenSSL-based PKCS#11 mode uses a modified version of the + OpenSSL library; stock OpenSSL does not fully support PKCS#11. + ISC provides a patch to OpenSSL to correct this. This patch is + based on work originally done by the OpenSolaris project; it has been + modified by ISC to provide new features such as PIN management and + key-by-reference. + </p> + <p> + There are two "flavors" of PKCS#11 support provided by + the patched OpenSSL, one of which must be chosen at + configuration time. The correct choice depends on the HSM + hardware: + </p> + <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> +<li class="listitem"> + <p> + Use 'crypto-accelerator' with HSMs that have hardware + cryptographic acceleration features, such as the SCA 6000 + board. This causes OpenSSL to run all supported + cryptographic operations in the HSM. + </p> + </li> +<li class="listitem"> + <p> + Use 'sign-only' with HSMs that are designed to + function primarily as secure key storage devices, but lack + hardware acceleration. These devices are highly secure, but + are not necessarily any faster at cryptography than the + system CPU — often, they are slower. It is therefore + most efficient to use them only for those cryptographic + functions that require access to the secured private key, + such as zone signing, and to use the system CPU for all + other computationally-intensive operations. The AEP Keyper + is an example of such a device. + </p> + </li> +</ul></div> + <p> + The modified OpenSSL code is included in the BIND 9 release, + in the form of a context diff against the latest versions of + OpenSSL. OpenSSL 0.9.8, 1.0.0, 1.0.1 and 1.0.2 are supported; + there are separate diffs for each version. In the examples to + follow, we use OpenSSL 0.9.8, but the same methods work with + OpenSSL 1.0.0 through 1.0.2. + </p> + <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"> +<h3 class="title">Note</h3> +<p> + The OpenSSL patches as of this writing (January 2016) + support versions 0.9.8zh, 1.0.0t, 1.0.1q and 1.0.2f. + ISC will provide updated patches as new versions of OpenSSL + are released. The version number in the following examples + is expected to change. + </p> +</div> + <p> + Before building BIND 9 with PKCS#11 support, it will be + necessary to build OpenSSL with the patch in place, and configure + it with the path to your HSM's PKCS#11 provider library. + </p> + <div class="section"> +<div class="titlepage"><div><div><h4 class="title"> +<a name="id-1.5.12.8.8"></a>Patching OpenSSL</h4></div></div></div> + + <pre class="screen"> +$ <strong class="userinput"><code>wget <a class="link" href="" target="_top">http://www.openssl.org/source/openssl-0.9.8zc.tar.gz</a></code></strong> + </pre> + <p>Extract the tarball:</p> + <pre class="screen"> +$ <strong class="userinput"><code>tar zxf openssl-0.9.8zc.tar.gz</code></strong> +</pre> + <p>Apply the patch from the BIND 9 release:</p> + <pre class="screen"> +$ <strong class="userinput"><code>patch -p1 -d openssl-0.9.8zc \ + < bind9/bin/pkcs11/openssl-0.9.8zc-patch</code></strong> +</pre> + <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"> +<h3 class="title">Note</h3> +<p> + The patch file may not be compatible with the + "patch" utility on all operating systems. You may need to + install GNU patch. + </p> +</div> + <p> + When building OpenSSL, place it in a non-standard + location so that it does not interfere with OpenSSL libraries + elsewhere on the system. In the following examples, we choose + to install into "/opt/pkcs11/usr". We will use this location + when we configure BIND 9. + </p> + <p> + Later, when building BIND 9, the location of the custom-built + OpenSSL library will need to be specified via configure. + </p> + </div> + <div class="section"> +<div class="titlepage"><div><div><h4 class="title"> +<a name="id-1.5.12.8.9"></a>Building OpenSSL for the AEP Keyper on Linux</h4></div></div></div> + + + <p> + The AEP Keyper is a highly secure key storage device, + but does not provide hardware cryptographic acceleration. It + can carry out cryptographic operations, but it is probably + slower than your system's CPU. Therefore, we choose the + 'sign-only' flavor when building OpenSSL. + </p> + <p> + The Keyper-specific PKCS#11 provider library is + delivered with the Keyper software. In this example, we place + it /opt/pkcs11/usr/lib: + </p> + <pre class="screen"> +$ <strong class="userinput"><code>cp pkcs11.GCC4.0.2.so.4.05 /opt/pkcs11/usr/lib/libpkcs11.so</code></strong> +</pre> + <p> + The Keyper library requires threads, so we + must specify -pthread. + </p> + <pre class="screen"> +$ <strong class="userinput"><code>cd openssl-0.9.8zc</code></strong> +$ <strong class="userinput"><code>./Configure linux-x86_64 -pthread \ + --pk11-libname=/opt/pkcs11/usr/lib/libpkcs11.so \ + --pk11-flavor=sign-only \ + --prefix=/opt/pkcs11/usr</code></strong> +</pre> + <p> + After configuring, run "<span class="command"><strong>make</strong></span>" + and "<span class="command"><strong>make test</strong></span>". If "<span class="command"><strong>make + test</strong></span>" fails with "pthread_atfork() not found", you forgot to + add the -pthread above. + </p> + </div> + <div class="section"> +<div class="titlepage"><div><div><h4 class="title"> +<a name="id-1.5.12.8.10"></a>Building OpenSSL for the SCA 6000 on Solaris</h4></div></div></div> + + + <p> + The SCA-6000 PKCS#11 provider is installed as a system + library, libpkcs11. It is a true crypto accelerator, up to 4 + times faster than any CPU, so the flavor shall be + 'crypto-accelerator'. + </p> + <p> + In this example, we are building on Solaris x86 on an + AMD64 system. + </p> + <pre class="screen"> +$ <strong class="userinput"><code>cd openssl-0.9.8zc</code></strong> +$ <strong class="userinput"><code>./Configure solaris64-x86_64-cc \ + --pk11-libname=/usr/lib/64/libpkcs11.so \ + --pk11-flavor=crypto-accelerator \ + --prefix=/opt/pkcs11/usr</code></strong> +</pre> + <p> + (For a 32-bit build, use "solaris-x86-cc" and /usr/lib/libpkcs11.so.) + </p> + <p> + After configuring, run + <span class="command"><strong>make</strong></span> and + <span class="command"><strong>make test</strong></span>. + </p> + </div> + <div class="section"> +<div class="titlepage"><div><div><h4 class="title"> +<a name="id-1.5.12.8.11"></a>Building OpenSSL for SoftHSM</h4></div></div></div> + + + <p> + SoftHSM (version 1) is a software library developed by the + OpenDNSSEC project + (<a class="link" href="http://www.opendnssec.org" target="_top"> + http://www.opendnssec.org + </a>) + which provides a + PKCS#11 interface to a virtual HSM, implemented in the form of + a SQLite3 database on the local filesystem. SoftHSM uses + the Botan library to perform cryptographic functions. Though + less secure than a true HSM, it can allow you to experiment + with PKCS#11 when an HSM is not available. + </p> + <p> + The SoftHSM cryptographic store must be installed and + initialized before using it with OpenSSL, and the SOFTHSM_CONF + environment variable must always point to the SoftHSM configuration + file: + </p> + <pre class="screen"> +$ <strong class="userinput"><code> cd softhsm-1.3.7 </code></strong> +$ <strong class="userinput"><code> configure --prefix=/opt/pkcs11/usr </code></strong> +$ <strong class="userinput"><code> make </code></strong> +$ <strong class="userinput"><code> make install </code></strong> +$ <strong class="userinput"><code> export SOFTHSM_CONF=/opt/pkcs11/softhsm.conf </code></strong> +$ <strong class="userinput"><code> echo "0:/opt/pkcs11/softhsm.db" > $SOFTHSM_CONF </code></strong> +$ <strong class="userinput"><code> /opt/pkcs11/usr/bin/softhsm --init-token 0 --slot 0 --label softhsm </code></strong> +</pre> + <p> + SoftHSM can perform all cryptographic operations, but + since it only uses your system CPU, there is no advantage to using + it for anything but signing. Therefore, we choose the 'sign-only' + flavor when building OpenSSL. + </p> + <pre class="screen"> +$ <strong class="userinput"><code>cd openssl-0.9.8zc</code></strong> +$ <strong class="userinput"><code>./Configure linux-x86_64 -pthread \ + --pk11-libname=/opt/pkcs11/usr/lib/libsofthsm.so \ + --pk11-flavor=sign-only \ + --prefix=/opt/pkcs11/usr</code></strong> +</pre> + <p> + After configuring, run "<span class="command"><strong>make</strong></span>" + and "<span class="command"><strong>make test</strong></span>". + </p> + </div> + <p> + Once you have built OpenSSL, run + "<span class="command"><strong>apps/openssl engine pkcs11</strong></span>" to confirm + that PKCS#11 support was compiled in correctly. The output + should be one of the following lines, depending on the flavor + selected: + </p> + <pre class="screen"> + (pkcs11) PKCS #11 engine support (sign only) +</pre> + <p>Or:</p> + <pre class="screen"> + (pkcs11) PKCS #11 engine support (crypto accelerator) +</pre> + <p> + Next, run + "<span class="command"><strong>apps/openssl engine pkcs11 -t</strong></span>". This will + attempt to initialize the PKCS#11 engine. If it is able to + do so successfully, it will report + <span class="quote">“<span class="quote"><code class="literal">[ available ]</code></span>”</span>. + </p> + <p> + If the output is correct, run + "<span class="command"><strong>make install</strong></span>" which will install the + modified OpenSSL suite to <code class="filename">/opt/pkcs11/usr</code>. + </p> + <div class="section"> +<div class="titlepage"><div><div><h4 class="title"> +<a name="id-1.5.12.8.18"></a>Configuring BIND 9 for Linux with the AEP Keyper</h4></div></div></div> + + + <p> + To link with the PKCS#11 provider, threads must be + enabled in the BIND 9 build. + </p> + <pre class="screen"> +$ <strong class="userinput"><code>cd ../bind9</code></strong> +$ <strong class="userinput"><code>./configure --enable-threads \ + --with-openssl=/opt/pkcs11/usr \ + --with-pkcs11=/opt/pkcs11/usr/lib/libpkcs11.so</code></strong> +</pre> + </div> + <div class="section"> +<div class="titlepage"><div><div><h4 class="title"> +<a name="id-1.5.12.8.19"></a>Configuring BIND 9 for Solaris with the SCA 6000</h4></div></div></div> + + + <p> + To link with the PKCS#11 provider, threads must be + enabled in the BIND 9 build. + </p> + <pre class="screen"> +$ <strong class="userinput"><code>cd ../bind9</code></strong> +$ <strong class="userinput"><code>./configure CC="cc -xarch=amd64" --enable-threads \ + --with-openssl=/opt/pkcs11/usr \ + --with-pkcs11=/usr/lib/64/libpkcs11.so</code></strong> +</pre> + <p>(For a 32-bit build, omit CC="cc -xarch=amd64".)</p> + <p> + If configure complains about OpenSSL not working, you + may have a 32/64-bit architecture mismatch. Or, you may have + incorrectly specified the path to OpenSSL (it should be the + same as the --prefix argument to the OpenSSL + Configure). + </p> + </div> + <div class="section"> +<div class="titlepage"><div><div><h4 class="title"> +<a name="id-1.5.12.8.20"></a>Configuring BIND 9 for SoftHSM</h4></div></div></div> + + + <pre class="screen"> +$ <strong class="userinput"><code>cd ../bind9</code></strong> +$ <strong class="userinput"><code>./configure --enable-threads \ + --with-openssl=/opt/pkcs11/usr \ + --with-pkcs11=/opt/pkcs11/usr/lib/libsofthsm.so</code></strong> +</pre> + </div> + <p> + After configuring, run + "<span class="command"><strong>make</strong></span>", + "<span class="command"><strong>make test</strong></span>" and + "<span class="command"><strong>make install</strong></span>". + </p> + <p> + (Note: If "make test" fails in the "pkcs11" system test, you may + have forgotten to set the SOFTHSM_CONF environment variable.) + </p> + </div> + <div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="id-1.5.12.9"></a>PKCS#11 Tools</h3></div></div></div> + + <p> + BIND 9 includes a minimal set of tools to operate the + HSM, including + <span class="command"><strong>pkcs11-keygen</strong></span> to generate a new key pair + within the HSM, + <span class="command"><strong>pkcs11-list</strong></span> to list objects currently + available, + <span class="command"><strong>pkcs11-destroy</strong></span> to remove objects, and + <span class="command"><strong>pkcs11-tokens</strong></span> to list available tokens. + </p> + <p> + In UNIX/Linux builds, these tools are built only if BIND + 9 is configured with the --with-pkcs11 option. (Note: If + --with-pkcs11 is set to "yes", rather than to the path of the + PKCS#11 provider, then the tools will be built but the + provider will be left undefined. Use the -m option or the + PKCS11_PROVIDER environment variable to specify the path to the + provider.) + </p> + </div> + <div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="id-1.5.12.10"></a>Using the HSM</h3></div></div></div> + + <p> + For OpenSSL-based PKCS#11, we must first set up the runtime + environment so the OpenSSL and PKCS#11 libraries can be loaded: + </p> + <pre class="screen"> +$ <strong class="userinput"><code>export LD_LIBRARY_PATH=/opt/pkcs11/usr/lib:${LD_LIBRARY_PATH}</code></strong> +</pre> + <p> + This causes <span class="command"><strong>named</strong></span> and other binaries to load + the OpenSSL library from <code class="filename">/opt/pkcs11/usr/lib</code> + rather than from the default location. This step is not necessary + when using native PKCS#11. + </p> + <p> + Some HSMs require other environment variables to be set. + For example, when operating an AEP Keyper, it is necessary to + specify the location of the "machine" file, which stores + information about the Keyper for use by the provider + library. If the machine file is in + <code class="filename">/opt/Keyper/PKCS11Provider/machine</code>, + use: + </p> + <pre class="screen"> +$ <strong class="userinput"><code>export KEYPER_LIBRARY_PATH=/opt/Keyper/PKCS11Provider</code></strong> +</pre> + <p> + Such environment variables must be set whenever running + any tool that uses the HSM, including + <span class="command"><strong>pkcs11-keygen</strong></span>, + <span class="command"><strong>pkcs11-list</strong></span>, + <span class="command"><strong>pkcs11-destroy</strong></span>, + <span class="command"><strong>dnssec-keyfromlabel</strong></span>, + <span class="command"><strong>dnssec-signzone</strong></span>, + <span class="command"><strong>dnssec-keygen</strong></span>, and + <span class="command"><strong>named</strong></span>. + </p> + <p> + We can now create and use keys in the HSM. In this case, + we will create a 2048 bit key and give it the label + "sample-ksk": + </p> + <pre class="screen"> +$ <strong class="userinput"><code>pkcs11-keygen -b 2048 -l sample-ksk</code></strong> +</pre> + <p>To confirm that the key exists:</p> + <pre class="screen"> +$ <strong class="userinput"><code>pkcs11-list</code></strong> +Enter PIN: +object[0]: handle 2147483658 class 3 label[8] 'sample-ksk' id[0] +object[1]: handle 2147483657 class 2 label[8] 'sample-ksk' id[0] +</pre> + <p> + Before using this key to sign a zone, we must create a + pair of BIND 9 key files. The "dnssec-keyfromlabel" utility + does this. In this case, we will be using the HSM key + "sample-ksk" as the key-signing key for "example.net": + </p> + <pre class="screen"> +$ <strong class="userinput"><code>dnssec-keyfromlabel -l sample-ksk -f KSK example.net</code></strong> +</pre> + <p> + The resulting K*.key and K*.private files can now be used + to sign the zone. Unlike normal K* files, which contain both + public and private key data, these files will contain only the + public key data, plus an identifier for the private key which + remains stored within the HSM. Signing with the private key takes + place inside the HSM. + </p> + <p> + If you wish to generate a second key in the HSM for use + as a zone-signing key, follow the same procedure above, using a + different keylabel, a smaller key size, and omitting "-f KSK" + from the dnssec-keyfromlabel arguments: + </p> + <p> + (Note: When using OpenSSL-based PKCS#11 the label is an arbitrary + string which identifies the key. With native PKCS#11, the label is + a PKCS#11 URI string which may include other details about the key + and the HSM, including its PIN. See + <a class="xref" href="man.dnssec-keyfromlabel.html" title="dnssec-keyfromlabel"><span class="refentrytitle"><span class="application">dnssec-keyfromlabel</span></span>(8)</a> for details.) + </p> + <pre class="screen"> +$ <strong class="userinput"><code>pkcs11-keygen -b 1024 -l sample-zsk</code></strong> +$ <strong class="userinput"><code>dnssec-keyfromlabel -l sample-zsk example.net</code></strong> +</pre> + <p> + Alternatively, you may prefer to generate a conventional + on-disk key, using dnssec-keygen: + </p> + <pre class="screen"> +$ <strong class="userinput"><code>dnssec-keygen example.net</code></strong> +</pre> + <p> + This provides less security than an HSM key, but since + HSMs can be slow or cumbersome to use for security reasons, it + may be more efficient to reserve HSM keys for use in the less + frequent key-signing operation. The zone-signing key can be + rolled more frequently, if you wish, to compensate for a + reduction in key security. (Note: When using native PKCS#11, + there is no speed advantage to using on-disk keys, as cryptographic + operations will be done by the HSM regardless.) + </p> + <p> + Now you can sign the zone. (Note: If not using the -S + option to <span class="command"><strong>dnssec-signzone</strong></span>, it will be + necessary to add the contents of both <code class="filename">K*.key</code> + files to the zone master file before signing it.) + </p> + <pre class="screen"> +$ <strong class="userinput"><code>dnssec-signzone -S example.net</code></strong> +Enter PIN: +Verifying the zone using the following algorithms: +NSEC3RSASHA1. +Zone signing complete: +Algorithm: NSEC3RSASHA1: ZSKs: 1, KSKs: 1 active, 0 revoked, 0 stand-by +example.net.signed +</pre> + </div> + <div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="id-1.5.12.11"></a>Specifying the engine on the command line</h3></div></div></div> + + <p> + When using OpenSSL-based PKCS#11, the "engine" to be used by + OpenSSL can be specified in <span class="command"><strong>named</strong></span> and all of + the BIND <span class="command"><strong>dnssec-*</strong></span> tools by using the "-E + <engine>" command line option. If BIND 9 is built with + the --with-pkcs11 option, this option defaults to "pkcs11". + Specifying the engine will generally not be necessary unless + for some reason you wish to use a different OpenSSL + engine. + </p> + <p> + If you wish to disable use of the "pkcs11" engine — + for troubleshooting purposes, or because the HSM is unavailable + — set the engine to the empty string. For example: + </p> + <pre class="screen"> +$ <strong class="userinput"><code>dnssec-signzone -E '' -S example.net</code></strong> +</pre> + <p> + This causes + <span class="command"><strong>dnssec-signzone</strong></span> to run as if it were compiled + without the --with-pkcs11 option. + </p> + <p> + When built with native PKCS#11 mode, the "engine" option has a + different meaning: it specifies the path to the PKCS#11 provider + library. This may be useful when testing a new provider library. + </p> + </div> + <div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="id-1.5.12.12"></a>Running named with automatic zone re-signing</h3></div></div></div> + + <p> + If you want <span class="command"><strong>named</strong></span> to dynamically re-sign zones + using HSM keys, and/or to to sign new records inserted via nsupdate, + then <span class="command"><strong>named</strong></span> must have access to the HSM PIN. In OpenSSL-based PKCS#11, + this is accomplished by placing the PIN into the openssl.cnf file + (in the above examples, + <code class="filename">/opt/pkcs11/usr/ssl/openssl.cnf</code>). + </p> + <p> + The location of the openssl.cnf file can be overridden by + setting the OPENSSL_CONF environment variable before running + <span class="command"><strong>named</strong></span>. + </p> + <p>Sample openssl.cnf:</p> + <pre class="programlisting"> + openssl_conf = openssl_def + [ openssl_def ] + engines = engine_section + [ engine_section ] + pkcs11 = pkcs11_section + [ pkcs11_section ] + PIN = <em class="replaceable"><code><PLACE PIN HERE></code></em> +</pre> + <p> + This will also allow the dnssec-* tools to access the HSM + without PIN entry. (The pkcs11-* tools access the HSM directly, + not via OpenSSL, so a PIN will still be required to use + them.) + </p> + <p> + In native PKCS#11 mode, the PIN can be provided in a file specified + as an attribute of the key's label. For example, if a key had the label + <strong class="userinput"><code>pkcs11:object=local-zsk;pin-source=/etc/hsmpin</code></strong>, + then the PIN would be read from the file + <code class="filename">/etc/hsmpin</code>. + </p> + <div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;"> +<h3 class="title">Warning</h3> + <p> + Placing the HSM's PIN in a text file in this manner may reduce the + security advantage of using an HSM. Be sure this is what you want to + do before configuring the system in this way. + </p> + </div> + </div> +</div> + + <div class="section"> +<div class="titlepage"><div><div><h2 class="title" style="clear: both"> +<a name="dlz-info"></a>DLZ (Dynamically Loadable Zones)</h2></div></div></div> + + <p> + DLZ (Dynamically Loadable Zones) is an extension to BIND 9 that allows + zone data to be retrieved directly from an external database. There is + no required format or schema. DLZ drivers exist for several different + database backends including PostgreSQL, MySQL, and LDAP and can be + written for any other. + </p> + <p> + Historically, DLZ drivers had to be statically linked with the <span class="command"><strong>named</strong></span> + binary and were turned on via a configure option at compile time (for + example, <strong class="userinput"><code>"configure --with-dlz-ldap"</code></strong>). + Currently, the drivers provided in the BIND 9 tarball in + <code class="filename">contrib/dlz/drivers</code> are still linked this + way. + </p> + <p> + In BIND 9.8 and higher, it is possible to link some DLZ modules + dynamically at runtime, via the DLZ "dlopen" driver, which acts as a + generic wrapper around a shared object implementing the DLZ API. The + "dlopen" driver is linked into <span class="command"><strong>named</strong></span> by default, so configure options + are no longer necessary when using these dynamically linkable drivers, + but are still needed for the older drivers in + <code class="filename">contrib/dlz/drivers</code>. + </p> + + <p> + When the DLZ module provides data to <span class="command"><strong>named</strong></span>, it does so in text format. + The response is converted to DNS wire format by <span class="command"><strong>named</strong></span>. This + conversion, and the lack of any internal caching, places significant + limits on the query performance of DLZ modules. Consequently, DLZ is + not recommended for use on high-volume servers. However, it can be + used in a hidden master configuration, with slaves retrieving zone + updates via AXFR. (Note, however, that DLZ has no built-in support for + DNS notify; slaves are not automatically informed of changes to the + zones in the database.) + </p> + + <div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="id-1.5.13.6"></a>Configuring DLZ</h3></div></div></div> + + <p> + A DLZ database is configured with a <span class="command"><strong>dlz</strong></span> + statement in <code class="filename">named.conf</code>: + </p> + <pre class="screen"> + dlz example { + database "dlopen driver.so <code class="option">args</code>"; + search yes; + }; + </pre> + <p> + This specifies a DLZ module to search when answering queries; the + module is implemented in <code class="filename">driver.so</code> and is + loaded at runtime by the dlopen DLZ driver. Multiple + <span class="command"><strong>dlz</strong></span> statements can be specified; when + answering a query, all DLZ modules with <code class="option">search</code> + set to <code class="literal">yes</code> will be queried to find out if + they contain an answer for the query name; the best available + answer will be returned to the client. + </p> + <p> + The <code class="option">search</code> option in the above example can be + omitted, because <code class="literal">yes</code> is the default value. + </p> + <p> + If <code class="option">search</code> is set to <code class="literal">no</code>, then + this DLZ module is <span class="emphasis"><em>not</em></span> searched for the best + match when a query is received. Instead, zones in this DLZ must be + separately specified in a zone statement. This allows you to + configure a zone normally using standard zone option semantics, + but specify a different database back-end for storage of the + zone's data. For example, to implement NXDOMAIN redirection using + a DLZ module for back-end storage of redirection rules: + </p> + <pre class="screen"> + dlz other { + database "dlopen driver.so <code class="option">args</code>"; + search no; + }; + + zone "." { + type redirect; + dlz other; + }; + </pre> + </div> + <div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="id-1.5.13.7"></a>Sample DLZ Driver</h3></div></div></div> + + <p> + For guidance in implementation of DLZ modules, the directory + <code class="filename">contrib/dlz/example</code> contains a basic + dynamically-linkable DLZ module--i.e., one which can be + loaded at runtime by the "dlopen" DLZ driver. + The example sets up a single zone, whose name is passed + to the module as an argument in the <span class="command"><strong>dlz</strong></span> + statement: + </p> + <pre class="screen"> + dlz other { + database "dlopen driver.so example.nil"; + }; + </pre> + <p> + In the above example, the module is configured to create a zone + "example.nil", which can answer queries and AXFR requests, and + accept DDNS updates. At runtime, prior to any updates, the zone + contains an SOA, NS, and a single A record at the apex: + </p> + <pre class="screen"> + example.nil. 3600 IN SOA example.nil. hostmaster.example.nil. ( + 123 900 600 86400 3600 + ) + example.nil. 3600 IN NS example.nil. + example.nil. 1800 IN A 10.53.0.1 + </pre> + <p> + The sample driver is capable of retrieving information about the + querying client, and altering its response on the basis of this + information. To demonstrate this feature, the example driver + responds to queries for "source-addr.<code class="option">zonename</code>>/TXT" + with the source address of the query. Note, however, that this + record will *not* be included in AXFR or ANY responses. Normally, + this feature would be used to alter responses in some other fashion, + e.g., by providing different address records for a particular name + depending on the network from which the query arrived. + </p> + <p> + Documentation of the DLZ module API can be found in + <code class="filename">contrib/dlz/example/README</code>. This directory also + contains the header file <code class="filename">dlz_minimal.h</code>, which + defines the API and should be included by any dynamically-linkable + DLZ module. + </p> + </div> +</div> + + <div class="section"> +<div class="titlepage"><div><div><h2 class="title" style="clear: both"> +<a name="dyndb-info"></a>DynDB (Dynamic Database)</h2></div></div></div> + + <p> + DynDB is an extension to BIND 9 which, like DLZ + (see <a class="xref" href="Bv9ARM.ch04.html#dlz-info" title="DLZ (Dynamically Loadable Zones)">the section called “DLZ (Dynamically Loadable Zones)”</a>), allows zone data to be + retrieved from an external database. Unlike DLZ, a DynDB module + provides a full-featured BIND zone database interface. Where + DLZ translates DNS queries into real-time database lookups, + resulting in relatively poor query performance, and is unable + to handle DNSSEC-signed data due to its limited API, a DynDB + module can pre-load an in-memory database from the external + data source, providing the same performance and functionality + as zones served natively by BIND. + </p> + <p> + A DynDB module supporting LDAP has been created by Red Hat + and is available from + <a class="link" href="https://fedorahosted.org/bind-dyndb-ldap/" target="_top">https://fedorahosted.org/bind-dyndb-ldap/</a>. + </p> + <p> + A sample DynDB module for testing and developer guidance + is included with the BIND source code, in the directory + <code class="filename">bin/tests/system/dyndb/driver</code>. + </p> + + <div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="id-1.5.14.5"></a>Configuring DynDB</h3></div></div></div> + + <p> + A DynDB database is configured with a <span class="command"><strong>dyndb</strong></span> + statement in <code class="filename">named.conf</code>: + </p> + <pre class="screen"> + dyndb example "driver.so" { + <em class="replaceable"><code>parameters</code></em> + }; + </pre> + <p> + The file <code class="filename">driver.so</code> is a DynDB module which + implements the full DNS database API. Multiple + <span class="command"><strong>dyndb</strong></span> statements can be specified, to load + different drivers or multiple instances of the same driver. + Zones provided by a DynDB module are added to the view's zone + table, and are treated as normal authoritative zones when BIND + is responding to queries. Zone configuration is handled internally + by the DynDB module. + </p> + <p> + The <em class="replaceable"><code>parameters</code></em> are passed as an opaque + string to the DynDB module's initialization routine. Configuration + syntax will differ depending on the driver. + </p> + </div> + <div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="id-1.5.14.6"></a>Sample DynDB Module</h3></div></div></div> + + <p> + For guidance in implementation of DynDB modules, the directory + <code class="filename">bin/tests/system/dyndb/driver</code>. + contains a basic DynDB module. + The example sets up two zones, whose names are passed + to the module as arguments in the <span class="command"><strong>dyndb</strong></span> + statement: + </p> + <pre class="screen"> + dyndb sample "sample.so" { example.nil. arpa. }; + </pre> + <p> + In the above example, the module is configured to create a zone + "example.nil", which can answer queries and AXFR requests, and + accept DDNS updates. At runtime, prior to any updates, the zone + contains an SOA, NS, and a single A record at the apex: + </p> + <pre class="screen"> + example.nil. 86400 IN SOA example.nil. example.nil. ( + 0 28800 7200 604800 86400 + ) + example.nil. 86400 IN NS example.nil. + example.nil. 86400 IN A 127.0.0.1 + </pre> + <p> + When the zone is updated dynamically, the DynDB module will determine + whether the updated RR is an address (i.e., type A or AAAA) and if + so, it will automatically update the corresponding PTR record in a + reverse zone. (Updates are not stored permanently; all updates are + lost when the server is restarted.) + </p> + </div> +</div> + + <div class="section"> +<div class="titlepage"><div><div><h2 class="title" style="clear: both"> +<a name="catz-info"></a>Catalog Zones</h2></div></div></div> + + <p> + A "catalog zone" is a special DNS zone that contains a list of + other zones to be served, along with their configuration parameters. + Zones listed in a catalog zone are called "member zones". + When a catalog zone is loaded or transferred to a slave server + which supports this functionality, the slave server will create + the member zones automatically. When the catalog zone is updated + (for example, to add or delete member zones, or change + their configuration parameters) those changes are immediately put + into effect. Because the catalog zone is a normal DNS zone, these + configuration changes can be propagated using the standard AXFR/IXFR + zone transfer mechanism. + </p> + <p> + Catalog zones' format and behavior are specified as an internet draft + for interoperability among DNS implementations. As of this release, the + latest revision of the DNS catalog zones draft can be found here: + https://datatracker.ietf.org/doc/draft-muks-dnsop-dns-catalog-zones/ + </p> + + <div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="id-1.5.15.4"></a>Principle of Operation</h3></div></div></div> + <p> + Normally, if a zone is to be served by a slave server, the + <code class="filename">named.conf</code> file on the server must list the + zone, or the zone must be added using <span class="command"><strong>rndc addzone</strong></span>. + In environments with a large number of slave servers and/or where + the zones being served are changing frequently, the overhead involved + in maintaining consistent zone configuration on all the slave + servers can be significant. + </p> + <p> + A catalog zone is a way to ease this administrative burden. It is a + DNS zone that lists member zones that should be served by slave servers. + When a slave server receives an update to the catalog zone, it adds, + removes, or reconfigures member zones based on the data received. + </p> + <p> + To use a catalog zone, it must first be set up as a normal zone on + the master and the on slave servers that will be configured to use + it. It must also be added to a <code class="option">catalog-zones</code> list + in the <code class="option">options</code> or <code class="option">view</code> statement + in <code class="filename">named.conf</code>. (This is comparable to the way + a policy zone is configured as a normal zone and also listed in + a <code class="option">response-policy</code> statement.) + </p> + <p> + To use the catalog zone feature to serve a new member zone: + </p> +<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> +<li class="listitem"> + <p> + Set up the the member zone to be served on the master as normal. + This could be done by editing <code class="filename">named.conf</code>, + or by running <span class="command"><strong>rndc addzone</strong></span>. + </p> + </li> +<li class="listitem"> + <p> + Add an entry to the catalog zone for the new member zone. + This could be done by editing the catalog zone's master file + and running <span class="command"><strong>rndc reload</strong></span>, or by updating + the zone using <span class="command"><strong>nsupdate</strong></span>. + </p> + </li> +</ul></div> +<p> + The change to the catalog zone will be propagated from the master to all + slaves using the normal AXFR/IXFR mechanism. When the slave receives the + update to the catalog zone, it will detect the entry for the new member + zone, create an instance of of that zone on the slave server, and point + that instance to the <code class="option">masters</code> specified in the catalog + zone data. The newly created member zone is a normal slave zone, so + BIND will immediately initiate a transfer of zone contents from the + master. Once complete, the slave will start serving the member zone. + </p> + <p> + Removing a member zone from a slave server requires nothing more than + deleting the member zone's entry in the catalog zone. The change to the + catalog zone is propagated to the slave server using the normal AXFR/IXFR + transfer mechanism. The slave server, on processing the update, will + notice that the member zone has been removed. It will stop serving the + zone and remove it from its list of configured zones. (Removing the + member zone from the master server has to be done in the normal way, + by editing the configuration file or running + <span class="command"><strong>rndc delzone</strong></span>.) + </p> + </div> + + <div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="id-1.5.15.5"></a>Configuring Catalog Zones</h3></div></div></div> + <p> + Catalog zones are configured with a <span class="command"><strong>catalog-zones</strong></span> + statement in the <code class="literal">options</code> or <code class="literal">view</code> + section of <code class="filename">named.conf</code>. For example, + </p> +<pre class="screen"> +catalog-zones { + zone "catalog.example" + default-masters { 10.53.0.1; } + in-memory no + zone-directory "catzones" + min-update-interval 10; +}; +</pre> + <p> + This statement specifies that the zone + <code class="literal">catalog.example</code> is a catalog zone. This zone must be + properly configured in the same view. In most configurations, it would + be a slave zone. + </p> + <p> + The options following the zone name are not required, and may be + specified in any order: + </p> + <p> + The <code class="option">default-masters</code> option defines the default masters + for member zones listed in a catalog zone. This can be overridden by + options within a catalog zone. If no such options are included, then + member zones will transfer their contents from the servers listed in + this option. + </p> + <p> + The <code class="option">in-memory</code> option, if set to <code class="literal">yes</code>, + causes member zones to be stored only in memory. This is functionally + equivalent to configuring a slave zone without a <code class="option">file</code>. + option. The default is <code class="literal">no</code>; member zones' content + will be stored locally in a file whose name is automatically generated + from the view name, catalog zone name, and member zone name. + </p> + <p> + The <code class="option">zone-directory</code> option causes local copies of + member zones' master files (if <code class="option">in-memory</code> is not set + to <code class="literal">yes</code>) to be stored in the specified directory. + The default is to store zone files in the server's working directory. + A non-absolute pathname in <code class="option">zone-directory</code> is + assumed to be relative to the working directory. + </p> + <p> + The <code class="option">min-update-interval</code> option sets the minimum + interval between processing of updates to catalog zones, in seconds. + If an update to a catalog zone (for example, via IXFR) happens less + than <code class="option">min-update-interval</code> seconds after the most + recent update, then the changes will not be carried out until this + interval has elapsed. The default is <code class="literal">5</code> seconds. + </p> + <p> + Catalog zones are defined on a per-view basis. Configuring a non-empty + <code class="option">catalog-zones</code> statement in a view will automatically + turn on <code class="option">allow-new-zones</code> for that view. (Note: this + means <span class="command"><strong>rndc addzone</strong></span> and <span class="command"><strong>rndc delzone</strong></span> + will also work in any view that supports catalog zones.) + </p> + </div> + + <div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="id-1.5.15.6"></a>Catalog Zone format</h3></div></div></div> + <p> + A catalog zone is a regular DNS zone; therefore, it has to have a + single <code class="literal">SOA</code> and at least one <code class="literal">NS</code> + record. + </p> + <p> + A record stating the version of the catalog zone format is + also required. If the version number listed is not supported by + the server, then a catalog zone may not be used by that server. + </p> +<pre class="screen"> +catalog.example. IN SOA . . 2016022901 900 600 86400 1 +catalog.example. IN NS nsexample. +version.catalog.example. IN TXT "1" +</pre> + <p> + Note that this record must have the domain name + version.<em class="replaceable"><code>catalog-zone-name</code></em>. This illustrates + how the meaning of data stored in a catalog zone is indicated by the + the domain name label immediately before the catalog zone domain. + </p> + <p> + Catalog zone options can be set either globally for the whole catalog + zone or for a single member zone. Global options override the settings + in the configuration file and member zone options override global + options. + </p> + <p> + Global options are set at the apex of the catalog zone, e.g.: +</p> +<pre class="screen"> + masters.catalog.example. IN AAAA 2001:db8::1 +</pre> + <p>BIND currently supports the following options:</p> + <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> +<li class="listitem"> + <p>A simple <code class="option">masters</code> definition:</p> + <pre class="screen"> + masters.catalog.example. IN A 192.0.2.1 + </pre> + <p> + This option defines a master server for the member zones - it + can be either an A or AAAA record. If multiple masters are set the + order in which they are used is random. + </p> + </li> +<li class="listitem"> + <p>A <code class="option">masters</code> with a TSIG key defined:</p> + <pre class="screen"> + label.masters.catalog.example. IN A 192.0.2.2 + label.masters.catalog.example. IN TXT "tsig_key_name" + </pre> + <p> + This option defines a master server for the member zone with a TSIG + key set. The TSIG key must be configured in the configuration file. + <code class="option">label</code> can be any valid DNS label. + </p> + </li> +<li class="listitem"> + <p><code class="option">allow-query</code> and + <code class="option">allow-transfer</code> ACLs:</p> + <pre class="screen"> + allow-query.catalog.example. IN APL 1:10.0.0.1/24 + allow-transfer.catalog.example. IN APL !1:10.0.0.1/32 1:10.0.0.0/24 + </pre> + <p> + These options are the equivalents of <code class="option">allow-query</code> + and <code class="option">allow-transfer</code> in a zone declaration in the + <code class="filename">named.conf</code> configuration file. The ACL is + processed in order - if there's no match to any rule the default + policy is to deny access. For the syntax of the APL RR see RFC + 3123 + </p> + </li> +</ul></div> + <p> + A member zone is added by including a <code class="literal">PTR</code> + resource record in the <code class="literal">zones</code> sub-domain of the + catalog zone. The record label is a <code class="literal">SHA-1</code> hash + of the member zone name in wire format. The target of the PTR + record is the member zone name. For example, to add the member + zone <code class="literal">domain.example</code>: + </p> +<pre class="screen"> +5960775ba382e7a4e09263fc06e7c00569b6a05c.zones.catalog.example. IN PTR domain.example. +</pre> + <p> + The hash is necessary to identify options for a specific member + zone. The member zone-specific options are defined the same way as + global options, but in the member zone subdomain: + </p> +<pre class="screen"> +masters.5960775ba382e7a4e09263fc06e7c00569b6a05c.zones.catalog.example. IN A 192.0.2.2 +label.masters.5960775ba382e7a4e09263fc06e7c00569b6a05c.zones.catalog.example. IN AAAA 2001:db8::2 +label.masters.5960775ba382e7a4e09263fc06e7c00569b6a05c.zones.catalog.example. IN TXT "tsig_key" +allow-query.5960775ba382e7a4e09263fc06e7c00569b6a05c.zones.catalog.example. IN APL 1:10.0.0.0/24 +</pre> + <p> + As would be expected, options defined for a specific zone override + the global options defined in the catalog zone. These in turn override + the global options defined in the <code class="literal">catalog-zones</code> + statement in the configuration file. + </p> + <p> + (Note that none of the global records an option will be inherited if + any records are defined for that option for the specific zone. For + example, if the zone had a <code class="literal">masters</code> record of type + A but not AAAA, then it would <span class="emphasis"><em>not</em></span> inherit the + type AAAA record from the global option.) + </p> + </div> +</div> + + <div class="section"> +<div class="titlepage"><div><div><h2 class="title" style="clear: both"> +<a name="ipv6"></a>IPv6 Support in <acronym class="acronym">BIND</acronym> 9</h2></div></div></div> + <p> + <acronym class="acronym">BIND</acronym> 9 fully supports all currently + defined forms of IPv6 name to address and address to name + lookups. It will also use IPv6 addresses to make queries when + running on an IPv6 capable system. + </p> + + <p> + For forward lookups, <acronym class="acronym">BIND</acronym> 9 supports + only AAAA records. RFC 3363 deprecated the use of A6 records, + and client-side support for A6 records was accordingly removed + from <acronym class="acronym">BIND</acronym> 9. + However, authoritative <acronym class="acronym">BIND</acronym> 9 name servers still + load zone files containing A6 records correctly, answer queries + for A6 records, and accept zone transfer for a zone containing A6 + records. + </p> + + <p> + For IPv6 reverse lookups, <acronym class="acronym">BIND</acronym> 9 supports + the traditional "nibble" format used in the + <span class="emphasis"><em>ip6.arpa</em></span> domain, as well as the older, deprecated + <span class="emphasis"><em>ip6.int</em></span> domain. + Older versions of <acronym class="acronym">BIND</acronym> 9 + supported the "binary label" (also known as "bitstring") format, + but support of binary labels has been completely removed per + RFC 3363. + Many applications in <acronym class="acronym">BIND</acronym> 9 do not understand + the binary label format at all any more, and will return an + error if given. + In particular, an authoritative <acronym class="acronym">BIND</acronym> 9 + name server will not load a zone file containing binary labels. + </p> + + <p> + For an overview of the format and structure of IPv6 addresses, + see <a class="xref" href="Bv9ARM.ch11.html#ipv6addresses" title="IPv6 addresses (AAAA)">the section called “IPv6 addresses (AAAA)”</a>. + </p> + + <div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="id-1.5.16.6"></a>Address Lookups Using AAAA Records</h3></div></div></div> + + <p> + The IPv6 AAAA record is a parallel to the IPv4 A record, + and, unlike the deprecated A6 record, specifies the entire + IPv6 address in a single record. For example, + </p> + +<pre class="programlisting"> +$ORIGIN example.com. +host 3600 IN AAAA 2001:db8::1 +</pre> + + <p> + Use of IPv4-in-IPv6 mapped addresses is not recommended. + If a host has an IPv4 address, use an A record, not + a AAAA, with <code class="literal">::ffff:192.168.42.1</code> as + the address. + </p> + </div> + <div class="section"> +<div class="titlepage"><div><div><h3 class="title"> +<a name="id-1.5.16.7"></a>Address to Name Lookups Using Nibble Format</h3></div></div></div> + + <p> + When looking up an address in nibble format, the address + components are simply reversed, just as in IPv4, and + <code class="literal">ip6.arpa.</code> is appended to the + resulting name. + For example, the following would provide reverse name lookup for + a host with address + <code class="literal">2001:db8::1</code>. + </p> + +<pre class="programlisting"> +$ORIGIN 0.0.0.0.0.0.0.0.8.b.d.0.1.0.0.2.ip6.arpa. +1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0 14400 IN PTR ( + host.example.com. ) +</pre> + + </div> + </div> + </div> +<div class="navfooter"> +<hr> +<table width="100%" summary="Navigation footer"> +<tr> +<td width="40%" align="left"> +<a accesskey="p" href="Bv9ARM.ch03.html">Prev</a> </td> +<td width="20%" align="center"> </td> +<td width="40%" align="right"> <a accesskey="n" href="Bv9ARM.ch05.html">Next</a> +</td> +</tr> +<tr> +<td width="40%" align="left" valign="top">Chapter 3. Name Server Configuration </td> +<td width="20%" align="center"><a accesskey="h" href="Bv9ARM.html">Home</a></td> +<td width="40%" align="right" valign="top"> Chapter 5. The <acronym class="acronym">BIND</acronym> 9 Lightweight Resolver</td> +</tr> +</table> +</div> +<p xmlns:db="http://docbook.org/ns/docbook" style="text-align: center;">BIND 9.11.5-P4 (Extended Support Version)</p> +</body> +</html> |