Release Notes for BIND Version 9.15.6

Introduction

BIND 9.15 is an unstable development release of BIND. This document
summarizes new features and functional changes that have been introduced
on this branch. With each development release leading up to the stable
BIND 9.16 release, this document will be updated with additional features
added and bugs fixed.

Note on Version Numbering

Until BIND 9.12, new feature development releases were tagged as "alpha"
and "beta", leading up to the first stable release for a given development
branch, which always ended in ".0". More recently, BIND adopted the
"odd-unstable/even-stable" release numbering convention. There will be no
"alpha" or "beta" releases in the 9.15 branch, only increasing version
numbers. So, for example, what would previously have been called 9.15.0a1,
9.15.0a2, 9.15.0b1, and so on, will instead be called 9.15.0, 9.15.1,
9.15.2, etc.

The first stable release from this development branch will be renamed as
9.16.0. Thereafter, maintenance releases will continue on the 9.16 branch,
while unstable feature development proceeds in 9.17.

Supported Platforms

To build on UNIX-like systems, BIND requires support for POSIX.1c threads
(IEEE Std 1003.1c-1995), the Advanced Sockets API for IPv6 (RFC 3542), and
standard atomic operations provided by the C compiler.

The OpenSSL cryptography library must be available for the target
platform. A PKCS#11 provider can be used instead for Public Key
cryptography (i.e., DNSSEC signing and validation), but OpenSSL is still
required for general cryptography operations such as hashing and random
number generation.

More information can be found in the PLATFORMS.md file that is included in
the source distribution of BIND 9. If your compiler and system libraries
provide the above features, BIND 9 should compile and run. If that isn't
the case, the BIND development team will generally accept patches that add
support for systems that are still supported by their respective vendors.

Download

The latest versions of BIND 9 software can always be found at https://
www.isc.org/download/. There you will find additional information about
each release, source code, and pre-compiled versions for Microsoft Windows
operating systems.

Notes for BIND 9.15.6

New Features

  * A new asynchronous network communications system based on libuv is now
    used by named for listening for incoming requests and responding to
    them. This change will make it easier to improve performance and
    implement new protocol layers (for example, DNS over TLS) in the
    future. [GL #29]

  * The new dnssec-policy option allows the configuration key and signing
    policy (KASP) for zones. This option enables named to generate new
    keys as needed and automatically roll both ZSK and KSK keys. (Note
    that the syntax for this statement differs from the DNSSEC policy used
    by dnssec-keymgr.) [GL #1134]

  * Two new keywords have been added to the dnssec-keys statement:
    initial-ds and static-ds. These allow the use of trust anchors in DS
    format instead of DNSKEY format. DS format allows trust anchors to be
    configured for keys that have not yet been published; this is the
    format used by IANA when announcing future root keys.

    As with the initial-key and static-key keywords, initial-ds configures
    a dynamic trust anchor to be maintained via RFC 5011, and static-ds
    configures a permanent trust anchor.

    (Note: Currently, DNSKEY-format and DS-format trust anchors cannot
    both be used for the same domain name.) [GL #6] [GL #622]

Feature Changes

  * NSEC Aggressive Cache (synth-from-dnssec) has been disabled by default
    because it was found to have a significant performance impact on the
    recursive service. The NSEC Aggressive Cache will be enable by default
    in the future releases. [GL #1265]

  * The DNSSEC validation code has been refactored for clarity and to
    reduce code duplication. [GL #622]

Security Fixes

  * Too many simultaneous pipelined TCP queries could cause resource
    overuse. We now prevent this by enforcing a limit on the number of
    simultaneous requests per active connection. This flaw`is disclosed in
    CVE-2019-6477. [GL #1264]

Notes for BIND 9.15.5

Security Fixes

  * named could crash with an assertion failure if a forwarder returned a
    referral, rather than resolving the query, when QNAME minimization was
    enabled. This flaw is disclosed in CVE-2019-6476. [GL #1051]

  * A flaw in DNSSEC verification when transferring mirror zones could
    allow data to be incorrectly marked valid. This flaw is disclosed in
    CVE-2019-6475. [GL #1252]

Notes for BIND 9.15.4

New Features

  * Added a new command line option to dig: +[no]unexpected. By default,
    dig won't accept a reply from a source other than the one to which it
    sent the query. Add the +unexpected argument to enable it to process
    replies from unexpected sources.

  * dig, mdig and delv can all now take a +yaml option to print output in
    a a detailed YAML format. [RT #1145]

Bug Fixes

  * When a response-policy zone expires, ensure that its policies are
    removed from the RPZ summary database. [GL #1146]

Notes for BIND 9.15.3

New Features

  * Statistics channel groups are now toggleable. [GL #1030]

Removed Features

  * DNSSEC Lookaside Validation (DLV) is now obsolete. The
    dnssec-lookaside option has been marked as deprecated; when used in
    named.conf, it will generate a warning but will otherwise be ignored.
    All code enabling the use of lookaside validation has been removed
    from the validator, delv, and the DNSSEC tools. [GL #7]

Feature Changes

  * A SipHash 2-4 based DNS Cookie (RFC 7873) algorithm has been added and
    made default. Old non-default HMAC-SHA based DNS Cookie algorithms
    have been removed, and only the default AES algorithm is being kept
    for legacy reasons. This change doesn't have any operational impact in
    most common scenarios. [GL #605]

    If you are running multiple DNS Servers (different versions of BIND 9
    or DNS server from multiple vendors) responding from the same IP
    address (anycast or load-balancing scenarios), you'll have to make
    sure that all the servers are configured with the same DNS Cookie
    algorithm and same Server Secret for the best performance.

  * The information from the dnssec-signzone and dnssec-verify commands is
    now printed to standard output. The standard error output is only used
    to print warnings and errors, and in case the user requests the signed
    zone to be printed to standard output with -f - option. A new
    configuration option -q has been added to silence all output on
    standard output except for the name of the signed zone.

  * DS records included in DNS referral messages can now be validated and
    cached immediately, reducing the number of queries needed for a DNSSEC
    validation. [GL #964]

Bug Fixes

  * Cache database statistics counters could report invalid values when
    stale answers were enabled, because of a bug in counter maintenance
    when cache data becomes stale. The statistics counters have been
    corrected to report the number of RRsets for each RR type that are
    active, stale but still potentially served, or stale and marked for
    deletion. [GL #602]

  * Interaction between DNS64 and RPZ No Data rule (CNAME *.) could cause
    unexpected results; this has been fixed. [GL #1106]

  * named-checkconf now checks DNS64 prefixes to ensure bits 64-71 are
    zero. [GL #1159]

  * named-checkconf now correctly reports a missing dnstap-output option
    when dnstap is set. [GL #1136]

  * Handle ETIMEDOUT error on connect() with a non-blocking socket. [GL #
    1133]

  * dig now correctly expands the IPv6 address when run with +expandaaaa
    +short. [GL #1152]

Notes for BIND 9.15.2

New Features

  * The GeoIP2 API from MaxMind is now supported. Geolocation support will
    be compiled in by default if the libmaxminddb library is found at
    compile time, but can be turned off by using configure --disable-geoip
    .

    The default path to the GeoIP2 databases will be set based on the
    location of the libmaxminddb library; for example, if it is in /usr/
    local/lib, then the default path will be /usr/local/share/GeoIP. This
    value can be overridden in named.conf using the geoip-directory
    option.

    Some geoip ACL settings that were available with legacy GeoIP,
    including searches for netspeed, org, and three-letter ISO country
    codes, will no longer work when using GeoIP2. Supported GeoIP2
    database types are country, city, domain, isp, and as. All of these
    databases support both IPv4 and IPv6 lookups. [GL #182] [GL #1112]

  * Two new metrics have been added to the statistics-channel to report
    DNSSEC signing operations. For each key in each zone, the dnssec-sign
    counter indicates the total number of signatures named has generated
    using that key since server startup, and the dnssec-refresh counter
    indicates how many of those signatures were refreshed during zone
    maintenance, as opposed to having been generated as a result of a zone
    update. [GL #513]

Bug Fixes

  * When qname-minimization was set to relaxed, some improperly configured
    domains would fail to resolve, but would have succeeded when
    minimization was disabled. named will now fall back to normal
    resolution in such cases, and also uses type A rather than NS for
    minimal queries in order to reduce the likelihood of encountering the
    problem. [GL #1055]

  * ./configure no longer sets --sysconfdir to /etc or --localstatedir to
    /var when --prefix is not specified and the aforementioned options are
    not specified explicitly. Instead, Autoconf's defaults of $prefix/etc
    and $prefix/var are respected.

  * Glue address records were not being returned in responses to root
    priming queries; this has been corrected. [GL #1092]

Notes for BIND 9.15.1

Security Fixes

  * A race condition could trigger an assertion failure when a large
    number of incoming packets were being rejected. This flaw is disclosed
    in CVE-2019-6471. [GL #942]

New Features

  * In order to clarify the configuration of DNSSEC keys, the trusted-keys
    and managed-keys statements have been deprecated, and the new
    dnssec-keys statement should now be used for both types of key.

    When used with the keyword initial-key, dnssec-keys has the same
    behavior as managed-keys, i.e., it configures a trust anchor that is
    to be maintained via RFC 5011.

    When used with the new keyword static-key, it has the same behavior as
    trusted-keys, configuring a permanent trust anchor that will not
    automatically be updated. (This usage is not recommended for the root
    key.) [GL #6]

Removed Features

  * The cleaning-interval option has been removed. [GL !1731]

Feature Changes

  * named will now log a warning if a static key is configured for the
    root zone. [GL #6]

  * JSON-C is now the only supported library for enabling JSON support for
    BIND statistics. The configure option has been renamed from
    --with-libjson to --with-json-c. Use PKG_CONFIG_PATH to specify a
    custom path to the json-c library as the new configure option does not
    take the library installation path as an optional argument.

Notes for BIND 9.15.0

Security Fixes

  * In certain configurations, named could crash with an assertion failure
    if nxdomain-redirect was in use and a redirected query resulted in an
    NXDOMAIN from the cache. This flaw is disclosed in CVE-2019-6467. [GL
    #880]

  * The TCP client quota set using the tcp-clients option could be
    exceeded in some cases. This could lead to exhaustion of file
    descriptors. This flaw is disclosed in CVE-2018-5743. [GL #615]

New Features

  * The new add-soa option specifies whether or not the response-policy
    zone's SOA record should be included in the additional section of RPZ
    responses. [GL #865]

Removed Features

  * The dnssec-enable option has been obsoleted and no longer has any
    effect. DNSSEC responses are always enabled if signatures and other
    DNSSEC data are present. [GL #866]

Feature Changes

  * When static and managed DNSSEC keys were both configured for the same
    name, or when a static key was used to configure a trust anchor for
    the root zone and dnssec-validation was set to the default value of
    auto, automatic RFC 5011 key rollovers would be disabled. This
    combination of settings was never intended to work, but there was no
    check for it in the parser. This has been corrected, and it is now a
    fatal configuration error. [GL #868]

  * DS and CDS records are now generated with SHA-256 digests only,
    instead of both SHA-1 and SHA-256. This affects the default output of
    dnssec-dsfromkey, the dsset files generated by dnssec-signzone, the DS
    records added to a zone by dnssec-signzone based on keyset files, the
    CDS records added to a zone by named and dnssec-signzone based on
    "sync" timing parameters in key files, and the checks performed by
    dnssec-checkds.

Bug Fixes

  * The allow-update and allow-update-forwarding options were
    inadvertently treated as configuration errors when used at the options
    or view level. This has now been corrected. [GL #913]

License

BIND is open source software licensed under the terms of the Mozilla
Public License, version 2.0 (see the LICENSE file for the full text).

The license requires that if you make changes to BIND and distribute them
outside your organization, those changes must be published under the same
license. It does not require that you publish or disclose anything other
than the changes you have made to our software. This requirement does not
affect anyone who is using BIND, with or without modifications, without
redistributing it, nor anyone redistributing BIND without changes.

Those wishing to discuss license compliance may contact ISC at https://
www.isc.org/mission/contact/.

End of Life

BIND 9.15 is an unstable development branch. When its development is
complete, it will be renamed to BIND 9.16, which will be a stable branch.

The end of life date for BIND 9.16 has not yet been determined. For those
needing long term support, the current Extended Support Version (ESV) is
BIND 9.11, which will be supported until at least December 2021. See
https://kb.isc.org/docs/aa-00896 for details of ISC's software support
policy.

Thank You

Thank you to everyone who assisted us in making this release possible. If
you would like to contribute to ISC to assist us in continuing to make
quality open source software, please visit our donations page at https://
www.isc.org/donate/.
