<!--
 - Copyright (C) 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 https://mozilla.org/MPL/2.0/.
 -
 - See the COPYRIGHT file distributed with this work for additional
 - information regarding copyright ownership.
-->

<section xml:id="relnotes-9.11.0"><info><title>Notes for BIND 9.11.0</title></info>

  <section xml:id="relnotes-9.11.0-security"><info><title>Security Fixes</title></info>
    <itemizedlist>
      <listitem>
        <para>
          It was possible to trigger a assertion when rendering a
          message using a specially crafted request. This flaw is
          disclosed in CVE-2016-2776. [RT #43139]
        </para>
      </listitem>
      <listitem>
        <para>
         getrrsetbyname with a non absolute name could trigger an
         infinite recursion bug in lwresd and named with lwres
         configured if when combined with a search list entry the
         resulting name is too long.  This flaw is disclosed in
         CVE-2016-2775. [RT #42694]
        </para>
      </listitem>
    </itemizedlist>
  </section>

  <section xml:id="relnotes-9.11.0-features"><info><title>New Features</title></info>
    <itemizedlist>
      <listitem>
        <para>
          A new method of provisioning secondary servers called
          "Catalog Zones" has been added. This is an implementation of
          <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="https://datatracker.ietf.org/doc/draft-muks-dnsop-dns-catalog-zones/">
            draft-muks-dnsop-dns-catalog-zones/
          </link>.
        </para>
        <para>
          A catalog zone is a regular DNS zone which contains a list
          of "member zones", along with the configuration options for
          each of those zones.  When a server is configured to use a
          catalog zone, all the zones listed in the catalog zone are
          added to the local server as slave zones.  When the catalog
          zone is updated (e.g., by adding or removing zones, or
          changing configuration options for existing zones) those
          changes will be put into effect.  Since the catalog zone is
          itself a DNS zone, this means configuration changes can be
          propagated to slaves using the standard AXFR/IXFR update
          mechanism.
        </para>
        <para>
          This feature should be considered experimental. It currently
          supports only basic features; more advanced features such as
          ACLs and TSIG keys are not yet supported. Example catalog
          zone configurations can be found in the Chapter 9 of the
          BIND Administrator Reference Manual.
        </para>
        <para>
          Support for master entries with TSIG keys has been added to catalog
          zones, as well as support for allow-query and allow-transfer.
        </para>
      </listitem>
      <listitem>
        <para>
          Added an <command>isc.rndc</command> Python module, which allows
          <command>rndc</command> commands to be sent from Python programs.
        </para>
      </listitem>
      <listitem>
        <para>
          Added support for DynDB, a new interface for loading zone data
          from an external database, developed by Red Hat for the FreeIPA
          project.  (Thanks in particular to Adam Tkac and Petr
          Spacek of Red Hat for the contribution.)
        </para>
        <para>
          Unlike the existing DLZ and SDB interfaces, which provide a
          limited subset of database functionality within BIND -
          translating DNS queries into real-time database lookups with
          relatively poor performance and with no ability to handle
          DNSSEC-signed data - DynDB is able to fully implement
          and extend the database API used natively by BIND.
        </para>
        <para>
          A DynDB module could pre-load data from an external data
          source, then serve it with the same performance and
          functionality as conventional BIND zones, and with the
          ability to take advantage of database features not
          available in BIND, such as multi-master replication.
        </para>
      </listitem>
      <listitem>
        <para>
          Fetch quotas are now compiled in by default: they
          no longer require BIND to be configured with
          <command>--enable-fetchlimit</command>, as was the case
          when the feature was introduced in BIND 9.10.3.
        </para>
        <para>
          These quotas limit the queries that are sent by recursive
          resolvers to authoritative servers experiencing denial-of-service
          attacks. They can both reduce the harm done to authoritative
          servers and also avoid the resource exhaustion that can be
          experienced by recursive servers when they are being used as a
          vehicle for such an attack.
        </para>
        <itemizedlist>
          <listitem>
            <para>
              <option>fetches-per-server</option> limits the number of
              simultaneous queries that can be sent to any single
              authoritative server.  The configured value is a starting
              point; it is automatically adjusted downward if the server is
              partially or completely non-responsive. The algorithm used to
              adjust the quota can be configured via the
              <option>fetch-quota-params</option> option.
            </para>
          </listitem>
          <listitem>
            <para>
              <option>fetches-per-zone</option> limits the number of
              simultaneous queries that can be sent for names within a
              single domain.  (Note: Unlike "fetches-per-server", this
              value is not self-tuning.)
            </para>
          </listitem>
        </itemizedlist>
        <para>
          Statistics counters have also been added to track the number
          of queries affected by these quotas.
        </para>
      </listitem>
      <listitem>
        <para>
          Added support for <command>dnstap</command>, a fast,
          flexible method for capturing and logging DNS traffic,
          developed by Robert Edmonds at Farsight Security, Inc.,
          whose assistance is gratefully acknowledged.
        </para>
        <para>
          To enable <command>dnstap</command> at compile time,
          the <command>fstrm</command> and <command>protobuf-c</command>
          libraries must be available, and BIND must be configured with
          <option>--enable-dnstap</option>.
        </para>
        <para>
          A new utility <command>dnstap-read</command> has been added
          to allow <command>dnstap</command> data to be presented in
          a human-readable format.
        </para>
        <para>
          <command>rndc dnstap -roll</command> causes <command>dnstap</command>
          output files to be rolled like log files -- the most recent output
          file is renamed with a <filename>.0</filename> suffix, the next
          most recent with <filename>.1</filename>, etc. (Note that this
          only works when <command>dnstap</command> output is being written
          to a file, not to a UNIX domain socket.) An optional numerical
          argument specifies how many backup log files to retain; if not
          specified or set to 0, there is no limit.
        </para>
        <para>
          <command>rndc dnstap -reopen</command> simply closes and reopens
          the <command>dnstap</command> output channel without renaming
          the output file.
        </para>
        <para>
          For more information on <command>dnstap</command>, see
          <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="https://dnstap.info">https://dnstap.info</link>.
        </para>
      </listitem>
      <listitem>
        <para>
          New statistics counters have been added to track traffic
          sizes, as specified in RSSAC002.  Query and response
          message sizes are broken up into ranges of histogram buckets:
          TCP and UDP queries of size 0-15, 16-31, ..., 272-288, and 288+,
          and TCP and UDP responses of size 0-15, 16-31, ..., 4080-4095,
          and 4096+.  These values can be accessed via the XML and JSON
          statistics channels at, for example,
          <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://localhost:8888/xml/v3/traffic">http://localhost:8888/xml/v3/traffic</link>
          or
          <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://localhost:8888/json/v1/traffic">http://localhost:8888/json/v1/traffic</link>.
        </para>
        <para>
                Statistics for RSSAC02v3 traffic-volume, traffic-sizes and
                rcode-volume reporting are now collected.
        </para>
      </listitem>
      <listitem>
        <para>
          A new DNSSEC key management utility,
          <command>dnssec-keymgr</command>, has been added. This tool
          is meant to run unattended (e.g., under <command>cron</command>).
          It reads a policy definition file
          (default <filename>/etc/dnssec-policy.conf</filename>)
          and creates or updates DNSSEC keys as necessary to ensure that a
          zone's keys match the defined policy for that zone.  New keys are
          created whenever necessary to ensure rollovers occur correctly.
          Existing keys' timing metadata is adjusted as needed to set the
          correct rollover period, prepublication interval, etc.  If
          the configured policy changes, keys are corrected automatically.
          See the <command>dnssec-keymgr</command> man page for full details.
        </para>
        <para>
          Note: <command>dnssec-keymgr</command> depends on Python and on
          the Python lex/yacc module, PLY. The other Python-based tools,
          <command>dnssec-coverage</command> and
          <command>dnssec-checkds</command>, have been
          refactored and updated as part of this work.
        </para>
        <para>
          <command>dnssec-keymgr</command> now takes a -r
          <replaceable>randomfile</replaceable> option.
        </para>
        <para>
          (Many thanks to Sebastián
          Castro for his assistance in developing this tool at the IETF
          95 Hackathon in Buenos Aires, April 2016.)
        </para>
      </listitem>
      <listitem>
        <para>
          The serial number of a dynamically updatable zone can
          now be set using
          <command>rndc signing -serial <replaceable>number</replaceable> <replaceable>zonename</replaceable></command>.
          This is particularly useful with <option>inline-signing</option>
          zones that have been reset.  Setting the serial number to a value
          larger than that on the slaves will trigger an AXFR-style
          transfer.
        </para>
      </listitem>
      <listitem>
        <para>
          When answering recursive queries, SERVFAIL responses can now be
          cached by the server for a limited time; subsequent queries for
          the same query name and type will return another SERVFAIL until
          the cache times out.  This reduces the frequency of retries
          when a query is persistently failing, which can be a burden
          on recursive servers.  The SERVFAIL cache timeout is controlled
          by <option>servfail-ttl</option>, which defaults to 1 second
          and has an upper limit of 30.
        </para>
      </listitem>
      <listitem>
        <para>
          The new <command>rndc nta</command> command can now be used to
          set a "negative trust anchor" (NTA), disabling DNSSEC validation for
          a specific domain; this can be used when responses from a domain
          are known to be failing validation due to administrative error
          rather than because of a spoofing attack. NTAs are strictly
          temporary; by default they expire after one hour, but can be
          configured to last up to one week.  The default NTA lifetime
          can be changed by setting the <option>nta-lifetime</option> in
          <filename>named.conf</filename>. When added, NTAs are stored in a
          file (<filename><replaceable>viewname</replaceable>.nta</filename>)
          in order to persist across restarts of the <command>named</command> server.
        </para>
      </listitem>
      <listitem>
        <para>
          The EDNS Client Subnet (ECS) option is now supported for
          authoritative servers; if a query contains an ECS option then
          ACLs containing <option>geoip</option> or <option>ecs</option>
          elements can match against the address encoded in the option.
          This can be used to select a view for a query, so that different
          answers can be provided depending on the client network.
        </para>
      </listitem>
      <listitem>
        <para>
          The EDNS EXPIRE option has been implemented on the client
          side, allowing a slave server to set the expiration timer
          correctly when transferring zone data from another slave
          server.
        </para>
      </listitem>
      <listitem>
        <para>
          A new <option>masterfile-style</option> zone option controls
          the formatting of text zone files:  When set to
          <literal>full</literal>, the zone file will dumped in
          single-line-per-record format.
        </para>
      </listitem>
      <listitem>
        <para>
          <command>dig +ednsopt</command> can now be used to set
          arbitrary EDNS options in DNS requests.
        </para>
      </listitem>
      <listitem>
        <para>
          <command>dig +ednsflags</command> can now be used to set
          yet-to-be-defined EDNS flags in DNS requests.
        </para>
      </listitem>
      <listitem>
        <para>
          <command>dig +[no]ednsnegotiation</command> can now be used enable /
          disable EDNS version negotiation.
        </para>
      </listitem>
      <listitem>
        <para>
          <command>dig +header-only</command> can now be used to send
          queries without a question section.
        </para>
      </listitem>
      <listitem>
        <para>
          <command>dig +ttlunits</command> causes <command>dig</command>
          to print TTL values with time-unit suffixes: w, d, h, m, s for
          weeks, days, hours, minutes, and seconds.
        </para>
      </listitem>
      <listitem>
        <para>
          <command>dig +zflag</command> can be used to set the last
          unassigned DNS header flag bit.  This bit is normally zero.
        </para>
      </listitem>
      <listitem>
        <para>
          <command>dig +dscp=<replaceable>value</replaceable></command>
          can now be used to set the DSCP code point in outgoing query
          packets.
        </para>
      </listitem>
      <listitem>
        <para>
          <command>dig +mapped</command> can now be used to determine
          if mapped IPv4 addresses can be used.
        </para>
      </listitem>
      <listitem>
        <para>
          <command>nslookup</command> will now look up IPv6 as well
          as IPv4 addresses by default. [RT #40420]
        </para>
      </listitem>
      <listitem>
        <para>
          <option>serial-update-method</option> can now be set to
          <literal>date</literal>. On update, the serial number will
          be set to the current date in YYYYMMDDNN format.
        </para>
      </listitem>
      <listitem>
        <para>
          <command>dnssec-signzone -N date</command> also sets the serial
          number to YYYYMMDDNN.
        </para>
      </listitem>
      <listitem>
        <para>
          <command>named -L <replaceable>filename</replaceable></command>
          causes <command>named</command> to send log messages to the
          specified file by default instead of to the system log.
        </para>
      </listitem>
      <listitem>
        <para>
          The rate limiter configured by the
          <option>serial-query-rate</option> option no longer covers
          NOTIFY messages; those are now separately controlled by
          <option>notify-rate</option> and
          <option>startup-notify-rate</option> (the latter of which
          controls the rate of NOTIFY messages sent when the server
          is first started up or reconfigured).
        </para>
      </listitem>
      <listitem>
        <para>
          The default number of tasks and client objects available
          for serving lightweight resolver queries have been increased,
          and are now configurable via the new <option>lwres-tasks</option>
          and <option>lwres-clients</option> options in
          <filename>named.conf</filename>. [RT #35857]
        </para>
      </listitem>
      <listitem>
        <para>
          Log output to files can now be buffered by specifying
          <command>buffered yes;</command> when creating a channel.
        </para>
      </listitem>
      <listitem>
        <para>
          <command>delv +tcp</command> will exclusively use TCP when
          sending queries.
        </para>
      </listitem>
      <listitem>
        <para>
          <command>named</command> will now check to see whether
          other name server processes are running before starting up.
          This is implemented in two ways: 1) by refusing to start
          if the configured network interfaces all return "address
          in use", and 2) by attempting to acquire a lock on a file
          specified by the <option>lock-file</option> option or
          the <command>-X</command> command line option.  The
          default lock file is
          <filename>/var/run/named/named.lock</filename>.
          Specifying <literal>none</literal> will disable the lock
          file check.
        </para>
      </listitem>
      <listitem>
        <para>
          <command>rndc delzone</command> can now be applied to zones
          which were configured in <filename>named.conf</filename>;
          it is no longer restricted to zones which were added by
          <command>rndc addzone</command>.  (Note, however, that
          this does not edit <filename>named.conf</filename>; the zone
          must be removed from the configuration or it will return
          when <command>named</command> is restarted or reloaded.)
        </para>
      </listitem>
      <listitem>
        <para>
          <command>rndc modzone</command> can be used to reconfigure
          a zone, using similar syntax to <command>rndc addzone</command>.
        </para>
      </listitem>
      <listitem>
        <para>
          <command>rndc showzone</command> displays the current
          configuration for a specified zone.
        </para>
      </listitem>
      <listitem>
        <para>
          When BIND is built with the <command>lmdb</command> library
          (Lightning Memory-Mapped Database), <command>named</command>
          will store the configuration information for zones
          that are added via <command>rndc addzone</command>
          in a database, rather than in a flat "NZF" file.  This
          dramatically improves performance for
          <command>rndc delzone</command> and
          <command>rndc modzone</command>: deleting or changing
          the contents of a database is much faster than rewriting
          a text file.
        </para>
        <para>
          On startup, if <command>named</command> finds an existing
          NZF file, it will automatically convert it to the new NZD
          database format.
        </para>
        <para>
          To view the contents of an NZD, or to convert an
          NZD back to an NZF file (for example, to revert back
          to an earlier version of BIND which did not support the
          NZD format), use the new command <command>named-nzd2nzf</command>
          [RT #39837]
        </para>
      </listitem>
      <listitem>
        <para>
          Added server-side support for pipelined TCP queries.  Clients
          may continue sending queries via TCP while previous queries are
          processed in parallel.  Responses are sent when they are
          ready, not necessarily in the order in which the queries were
          received.
        </para>
        <para>
          To revert to the former behavior for a particular
          client address or range of addresses, specify the address prefix
          in the "keep-response-order" option.  To revert to the former
          behavior for all clients, use "keep-response-order { any; };".
        </para>
      </listitem>
      <listitem>
        <para>
          The new <command>mdig</command> command is a version of
          <command>dig</command> that sends multiple pipelined
          queries and then waits for responses, instead of sending one
          query and waiting the response before sending the next. [RT #38261]
        </para>
      </listitem>
      <listitem>
        <para>
          To enable better monitoring and troubleshooting of RFC 5011
          trust anchor management, the new <command>rndc managed-keys</command>
          can be used to check status of trust anchors or to force keys
          to be refreshed.  Also, the managed-keys data file now has
          easier-to-read comments. [RT #38458]
        </para>
      </listitem>
      <listitem>
        <para>
          An <command>--enable-querytrace</command> configure switch is
          now available to enable very verbose query trace logging. This
          option can only be set at compile time. This option has a
          negative performance impact and should be used only for
          debugging. [RT #37520]
        </para>
      </listitem>
      <listitem>
        <para>
          A new <command>tcp-only</command> option can be specified
          in <command>server</command> statements to force
          <command>named</command> to connect to the specified
          server via TCP. [RT #37800]
        </para>
      </listitem>
      <listitem>
        <para>
          The <command>nxdomain-redirect</command> option specifies
          a DNS namespace to use for NXDOMAIN redirection. When a
          recursive lookup returns NXDOMAIN, a second lookup is
          initiated with the specified name appended to the query
          name. This allows NXDOMAIN redirection data to be supplied
          by multiple zones configured on the server, or by recursive
          queries to other servers. (The older method, using
          a single <command>type redirect</command> zone, has
          better average performance but is less flexible.) [RT #37989]
        </para>
      </listitem>
      <listitem>
        <para>
          The following types have been implemented: CSYNC, NINFO, RKEY,
          SINK, TA, TALINK.
        </para>
      </listitem>
      <listitem>
        <para>
          A new <command>message-compression</command> option can be
          used to specify whether or not to use name compression when
          answering queries. Setting this to <userinput>no</userinput>
          results in larger responses, but reduces CPU consumption and
          may improve throughput.  The default is <userinput>yes</userinput>.
        </para>
      </listitem>
      <listitem>
        <para>
          A <command>read-only</command> option is now available in the
          <command>controls</command> statement to grant non-destructive
          control channel access. In such cases, a restricted set of
          <command>rndc</command> commands are allowed, which can
          report information from <command>named</command>, but cannot
          reconfigure or stop the server. By default, the control channel
          access is <emphasis>not</emphasis> restricted to these
          read-only operations. [RT #40498]
        </para>
      </listitem>
      <listitem>
        <para>
          When loading a signed zone, <command>named</command> will
          now check whether an RRSIG's inception time is in the future,
          and if so, it will regenerate the RRSIG immediately. This helps
          when a system's clock needs to be reset backwards.
        </para>
      </listitem>
      <listitem>
        <para>
          The new <command>minimal-any</command> option reduces the size
          of answers to UDP queries for type ANY by implementing one of
          the strategies in "draft-ietf-dnsop-refuse-any": returning
          a single arbitrarily-selected RRset that matches the query
          name rather than returning all of the matching RRsets.
          Thanks to Tony Finch for the contribution. [RT #41615]
        </para>
      </listitem>
      <listitem>
        <para>
          <command>named</command> now provides feedback to the
          owners of zones which have trust anchors configured
          (<command>trusted-keys</command>,
          <command>managed-keys</command>, <command>dnssec-validation
          auto;</command> and <command>dnssec-lookaside auto;</command>)
          by sending a daily query which encodes the keyids of the
          configured trust anchors for the zone.  This is controlled
          by <command>trust-anchor-telemetry</command> and defaults
          to yes.
        </para>
      </listitem>
    </itemizedlist>
  </section>

  <section xml:id="relnotes-9.11.0-changes"><info><title>Feature Changes</title></info>
    <itemizedlist>
      <listitem>
        <para>
          The logging format used for <command>querylog</command> has been
          altered. It now includes an additional field indicating the
          address in memory of the client object processing the query.
        </para>
        <para>
          The ISC DNSSEC Lookaside Validation (DLV) service is scheduled
          to be disabled in 2017.  A warning is now logged when
          <command>named</command> is configured to use this service,
          either explicitly or via <option>dnssec-lookaside auto;</option>.
          [RT #42207]
        </para>
      </listitem>
      <listitem>
        <para>
          The timers returned by the statistics channel (indicating current
          time, server boot time, and most recent reconfiguration time) are
          now reported with millisecond accuracy. [RT #40082]
        </para>
      </listitem>
      <listitem>
        <para>
          Updated the compiled-in addresses for H.ROOT-SERVERS.NET
          and L.ROOT-SERVERS.NET.
        </para>
      </listitem>
      <listitem>
        <para>
          ACLs containing <command>geoip asnum</command> elements were
          not correctly matched unless the full organization name was
          specified in the ACL (as in
          <command>geoip asnum "AS1234 Example, Inc.";</command>).
          They can now match against the AS number alone (as in
          <command>geoip asnum "AS1234";</command>).
        </para>
      </listitem>
      <listitem>
        <para>
          When using native PKCS#11 cryptography (i.e.,
          <command>configure --enable-native-pkcs11</command>) HSM PINs
          of up to 256 characters can now be used.
        </para>
      </listitem>
      <listitem>
        <para>
          NXDOMAIN responses to queries of type DS are now cached separately
          from those for other types. This helps when using "grafted" zones
          of type forward, for which the parent zone does not contain a
          delegation, such as local top-level domains.  Previously a query
          of type DS for such a zone could cause the zone apex to be cached
          as NXDOMAIN, blocking all subsequent queries.  (Note: This
          change is only helpful when DNSSEC validation is not enabled.
          "Grafted" zones without a delegation in the parent are not a
          recommended configuration.)
        </para>
      </listitem>
      <listitem>
        <para>
          Update forwarding performance has been improved by allowing
          a single TCP connection to be shared between multiple updates.
        </para>
      </listitem>
      <listitem>
        <para>
          By default, <command>nsupdate</command> will now check
          the correctness of hostnames when adding records of type
          A, AAAA, MX, SOA, NS, SRV or PTR.  This behavior can be
          disabled with <command>check-names no</command>.
        </para>
      </listitem>
      <listitem>
        <para>
          Added support for OPENPGPKEY type.
        </para>
      </listitem>
      <listitem>
        <para>
          The names of the files used to store managed keys and added
          zones for each view are no longer based on the SHA256 hash
          of the view name, except when this is necessary because the
          view name contains characters that would be incompatible with use
          as a file name.  For views whose names do not contain forward
          slashes ('/'), backslashes ('\'), or capital letters - which
          could potentially cause namespace collision problems on
          case-insensitive filesystems - files will now be named
          after the view (for example, <filename>internal.mkeys</filename>
          or <filename>external.nzf</filename>).  However, to ensure
          consistent behavior when upgrading, if a file using the old
          name format is found to exist, it will continue to be used.
        </para>
      </listitem>
      <listitem>
        <para>
          "rndc" can now return text output of arbitrary size to
          the caller. (Prior to this, certain commands such as
          "rndc tsig-list" and "rndc zonestatus" could return
          truncated output.)
        </para>
      </listitem>
      <listitem>
        <para>
          Errors reported when running <command>rndc addzone</command>
          (e.g., when a zone file cannot be loaded) have been clarified
          to make it easier to diagnose problems.
        </para>
      </listitem>
      <listitem>
        <para>
          When encountering an authoritative name server whose name is
          an alias pointing to another name, the resolver treats
          this as an error and skips to the next server. Previously
          this happened silently; now the error will be logged to
          the newly-created "cname" log category.
        </para>
      </listitem>
      <listitem>
        <para>
          If <command>named</command> is not configured to validate
          answers, then allow fallback to plain DNS on timeout even when
          we know the server supports EDNS.  This will allow the server to
          potentially resolve signed queries when TCP is being
          blocked.
        </para>
      </listitem>
      <listitem>
        <para>
          Large inline-signing changes should be less disruptive.
          Signature generation is now done incrementally; the number
          of signatures to be generated in each quantum is controlled
          by "sig-signing-signatures <replaceable>number</replaceable>;".
          [RT #37927]
        </para>
      </listitem>
      <listitem>
        <para>
          The experimental SIT option (code point 65001) of BIND
          9.10.0 through BIND 9.10.2 has been replaced with the COOKIE
          option (code point 10). It is no longer experimental, and
          is sent by default, by both <command>named</command> and
          <command>dig</command>.
        </para>
        <para>
          The SIT-related named.conf options have been marked as
          obsolete, and are otherwise ignored.
        </para>
      </listitem>
      <listitem>
        <para>
          When <command>dig</command> receives a truncated (TC=1)
          response or a BADCOOKIE response code from a server, it
          will automatically retry the query using the server COOKIE
          that was returned by the server in its initial response.
          [RT #39047]
        </para>
      </listitem>
      <listitem>
        <para>
          Retrieving the local port range from net.ipv4.ip_local_port_range
          on Linux is now supported.
        </para>
      </listitem>
      <listitem>
        <para>
          A new <option>nsip-wait-recurse</option> directive has been
          added to RPZ, specifying whether to look up unknown name server
          IP addresses and wait for a response before applying RPZ-NSIP rules.
          The default is <userinput>yes</userinput>. If set to
          <userinput>no</userinput>, <command>named</command> will only
          apply RPZ-NSIP rules to servers whose addresses are already cached.
          The addresses will be looked up in the background so the rule can
          be applied on subsequent queries. This improves performance when
          the cache is cold, at the cost of temporary imprecision in applying
          policy directives. [RT #35009]
        </para>
      </listitem>
      <listitem>
        <para>
          Within the <option>response-policy</option> option, it is now
          possible to configure RPZ rewrite logging on a per-zone basis
          using the <option>log</option> clause.
        </para>
      </listitem>
      <listitem>
        <para>
          The default preferred glue is now the address type of the
          transport the query was received over.
        </para>
      </listitem>
      <listitem>
        <para>
          On machines with 2 or more processors (CPU), the default value
          for the number of UDP listeners has been changed to the number
          of detected processors minus one.
        </para>
      </listitem>
      <listitem>
        <para>
          Zone transfers now use smaller message sizes to improve
          message compression. This results in reduced network usage.
        </para>
      </listitem>
      <listitem>
        <para>
          Added support for the AVC resource record type (Application
          Visibility and Control).
        </para>
        <para>
          Changed <command>rndc reconfig</command> behavior so that newly
          added zones are loaded asynchronously and the loading does not
          block the server.
        </para>
      </listitem>
      <listitem>
        <para>
          <command>minimal-responses</command> now takes two new
          arguments: <option>no-auth</option> suppresses
          populating the authority section but not the additional
          section; <option>no-auth-recursive</option>
          does the same but only when answering recursive queries.
        </para>
      </listitem>
      <listitem>
        <para>
          At server startup time, the queues for processing
          notify and zone refresh queries are now processed in
          LIFO rather than FIFO order, to speed up
          loading of newly added zones. [RT #42825]
        </para>
      </listitem>
      <listitem>
        <para>
          When answering queries of type MX or SRV, TLSA records for
          the target name are now included in the additional section
          to speed up DANE processing. [RT #42894]
        </para>
      </listitem>
      <listitem>
        <para>
          <command>named</command> can now use the TCP Fast Open
          mechanism on the server side, if supported by the
          local operating system. [RT #42866]
        </para>
      </listitem>
    </itemizedlist>
  </section>

  <section xml:id="relnotes-9.11.0-bugs"><info><title>Bug Fixes</title></info>
    <itemizedlist>
      <listitem>
        <para>
          Fixed a crash when calling <command>rndc stats</command> on some
          Windows builds: some Visual Studio compilers generate code that
          crashes when the "%z" printf() format specifier is used. [RT #42380]
        </para>
      </listitem>
      <listitem>
        <para>
          Windows installs were failing due to triggering UAC without
          the installation binary being signed.
        </para>
      </listitem>
      <listitem>
        <para>
          A change in the internal binary representation of the RBT database
          node structure enabled a race condition to occur (especially when
          BIND was built with certain compilers or optimizer settings),
          leading to inconsistent database state which caused random
          assertion failures. [RT #42380]
        </para>
      </listitem>
    </itemizedlist>
  </section>

</section>
