bind9/doc/arm/notes.txt

Release Notes for BIND Version 9.13.6

Introduction

BIND 9.13 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 9.14 release, this document will be updated with additional features
added and bugs fixed.

Note on Version Numbering

Prior to BIND 9.13, 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".

Now, however, BIND has adopted the "odd-unstable/even-stable" release
numbering convention. There will be no "alpha" or "beta" releases in the
9.13 branch, only increasing version numbers. So, for example, what would
previously have been called 9.13.0a1, 9.13.0a2, 9.13.0b1, and so on, will
instead be called 9.13.0, 9.13.1, 9.13.2, etc.

The first stable release from this development branch will be renamed as
9.14.0. Thereafter, maintenance releases will continue on the 9.14 branch,
while unstable feature development proceeds in 9.15.

Supported Platforms

BIND 9.13 has undergone substantial code refactoring and cleanup, and some
very old code has been removed that was needed to support legacy platforms
which are no longer supported by their vendors and for which ISC is no
longer able to perform quality assurance testing. Specifically,
workarounds for old versions of UnixWare, BSD/OS, AIX, Tru64, SunOS,
TruCluster and IRIX have been removed. On UNIX-like systems, BIND now
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.

More information can be found in the PLATFORM.md file that is included in
the source distribution of BIND 9. If your platform 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.

As of BIND 9.13, the BIND development team has also made cryptography
(i.e., TSIG and DNSSEC) an integral part of the DNS server. 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.

Download

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

Security Fixes

  * There was a long-existing flaw in the documentation for ms-self,
    krb5-self, ms-subdomain, and krb5-subdomain rules in update-policy
    statements. Though the policies worked as intended, operators who
    configured their servers according to the misleading documentation may
    have thought zone updates were more restricted than they were; users
    of these rule types are advised to review the documentation and
    correct their configurations if necessary. New rule types matching the
    previously documented behavior will be introduced in a future
    maintenance release. [GL !708]

  * When recursion is enabled but the allow-recursion and
    allow-query-cache ACLs are not specified, they should be limited to
    local networks, but they were inadvertently set to match the default
    allow-query, thus allowing remote queries. This flaw is disclosed in
    CVE-2018-5738. [GL #309]

  * named could crash during recursive processing of DNAME records when
    deny-answer-aliases was in use. This flaw is disclosed in
    CVE-2018-5740. [GL #387]

  * Code change #4964, intended to prevent double signatures when deleting
    an inactive zone DNSKEY in some situations, introduced a new problem
    during zone processing in which some delegation glue RRsets are
    incorrectly identified as needing RRSIGs, which are then created for
    them using the current active ZSK for the zone. In some, but not all
    cases, the newly-signed RRsets are added to the zone's NSEC/NSEC3
    chain, but incompletely -- this can result in a broken chain,
    affecting validation of proof of nonexistence for records in the zone.
    [GL #771]

New Features

  * Task manager and socket code have been substantially modified. The
    manager uses per-cpu queues for tasks and network stack runs multiple
    event loops in CPU-affinitive threads. This greatly improves
    performance on large systems, especially when using multi-queue NICs.

  * A new secondary zone option, mirror, enables named to serve a
    transferred copy of a zone's contents without acting as an authority
    for the zone. A zone must be fully validated against an active trust
    anchor before it can be used as a mirror zone. DNS responses from
    mirror zones do not set the AA bit ("authoritative answer"), but do
    set the AD bit ("authenticated data"). This feature is meant to
    facilitate deployment of a local copy of the root zone, as described
    in RFC 7706. [GL #33]

  * A new plugin mechanism has been added to allow extension of query
    processing functionality through the use of external libraries. The
    new filter-aaaa.so plugin replaces the filter-aaaa feature that was
    formerly implemented as a native part of BIND.

    The plugin API is a work in progress and is likely to evolve as
    further plugins are implemented. [GL #15]

  * BIND now can be compiled against the libidn2 library to add IDNA2008
    support. Previously, BIND supported IDNA2003 using the (now obsolete
    and unsupported) idnkit-1 library.

  * named now supports the "root key sentinel" mechanism. This enables
    validating resolvers to indicate which trust anchors are configured
    for the root, so that information about root key rollover status can
    be gathered. To disable this feature, add root-key-sentinel no; to
    named.conf. [GL #37]

  * The dnskey-sig-validity option allows the sig-validity-interval to be
    overriden for signatures covering DNSKEY RRsets. [GL #145]

  * Support for QNAME minimization was added and enabled by default in
    relaxed mode, in which BIND will fall back to normal resolution if the
    remote server returns something unexpected during the query
    minimization process. This default setting might change to strict in
    the future.

  * When built on Linux, BIND now requires the libcap library to set
    process privileges. The adds a new compile-time dependency, which can
    be met on most Linux platforms by installing the libcap-dev or
    libcap-devel package. BIND can also be built without capability
    support by using configure --disable-linux-caps, at the cost of some
    loss of security.

  * The validate-except option specifies a list of domains beneath which
    DNSSEC validation should not be performed, regardless of whether a
    trust anchor has been configured above them. [GL #237]

  * Two new update policy rule types have been added krb5-selfsub and
    ms-selfsub which allow machines with Kerberos principals to update the
    name space at or below the machine names identified in the respective
    principals.

  * The new configure option --enable-fips-mode can be used to make BIND
    enable and enforce FIPS mode in the OpenSSL library. When compiled
    with such option the BIND will refuse to run if FIPS mode can't be
    enabled, thus this option must be only enabled for the systems where
    FIPS mode is available.

  * Two new configuration options min-cache-ttl and min-ncache-ttl has
    been added to allow the BIND 9 administrator to override the minimum
    TTL in the received DNS records (positive caching) and for storing the
    information about non-existent records (negative caching). The
    configured minimum TTL for both configuration options cannot exceed 90
    seconds.

  * rndc status output now includes a reconfig/reload in progress status
    line if named configuration is being reloaded.

Removed Features

  * Workarounds for servers that misbehave when queried with EDNS have
    been removed, because these broken servers and the workarounds for
    their noncompliance cause unnecessary delays, increase code
    complexity, and prevent deployment of new DNS features. See https://
    dnsflagday.net for further details.

    In particular, resolution will no longer fall back to plain DNS when
    there was no response from an authoritative server. This will cause
    some domains to become non-resolvable without manual intervention. In
    these cases, resolution can be restored by adding server clauses for
    the offending servers, specifying edns no or send-cookie no, depending
    on the specific noncompliance.

    To determine which server clause to use, run the following commands to
    send queries to the authoritative servers for the broken domain:


      dig soa <zone> @<server> +dnssec
      dig soa <zone> @<server> +dnssec +nocookie
      dig soa <zone> @<server> +noedns

    If the first command fails but the second succeeds, the server most
    likely needs send-cookie no. If the first two fail but the third
    succeeds, then the server needs EDNS to be fully disabled with edns no
    .

    Please contact the administrators of noncompliant domains and
    encourage them to upgrade their broken DNS servers. [GL #150]

  * Previously, it was possible to build BIND without thread support for
    old architectures and systems without threads support. BIND now
    requires threading support (either POSIX or Windows) from the
    operating system, and it cannot be built without threads.

  * The filter-aaaa, filter-aaaa-on-v4, and filter-aaaa-on-v6 options have
    been removed from named, and can no longer be configured using native
    named.conf syntax. However, loading the new filter-aaaa.so plugin and
    setting its parameters provides identical functionality.

  * named can no longer use the EDNS CLIENT-SUBNET option for view
    selection. In its existing form, the authoritative ECS feature was not
    fully RFC-compliant, and could not realistically have been deployed in
    production for an authoritative server; its only practical use was for
    testing and experimentation. In the interest of code simplification,
    this feature has now been removed.

    The ECS option is still supported in dig and mdig via the +subnet
    argument, and can be parsed and logged when received by named, but it
    is no longer used for ACL processing. The geoip-use-ecs option is now
    obsolete; a warning will be logged if it is used in named.conf. ecs
    tags in an ACL definition are also obsolete, and will cause the
    configuration to fail to load if they are used. [GL #32]

  * dnssec-keygen can no longer generate HMAC keys for TSIG
    authentication. Use tsig-keygen to generate these keys. [RT #46404]

  * Support for OpenSSL 0.9.x has been removed. OpenSSL version 1.0.0 or
    greater, or LibreSSL is now required.

  * The configure --enable-seccomp option, which formerly turned on
    system-call filtering on Linux, has been removed. [GL #93]

  * IPv4 addresses in forms other than dotted-quad are no longer accepted
    in master files. [GL #13] [GL #56]

  * IDNA2003 support via (bundled) idnkit-1.0 has been removed.

  * The "rbtdb64" database implementation (a parallel implementation of
    "rbt") has been removed. [GL #217]

  * The -r randomdev option to explicitly select random device has been
    removed from the ddns-confgen, rndc-confgen, nsupdate, dnssec-confgen,
    and dnssec-signzone commands.

    The -p option to use pseudo-random data has been removed from the
    dnssec-signzone command.

  * Support for ECC-GOST (GOST R 34.11-94) algorithm has been removed from
    BIND as the algorithm has been superseded by GOST R 34.11-2012 in
    RFC6986 and it must not be used in new deployments. BIND will neither
    create new DNSSEC keys, signatures and digest, nor it will validate
    them.

  * Add the ability to not return a DNS COOKIE option when one is present
    in the request. To prevent a cookie being returned add 'answer-cookie
    no;' to named.conf. [GL #173]

    answer-cookie is only intended as a temporary measure, for use when
    named shares an IP address with other servers that do not yet support
    DNS COOKIE. A mismatch between servers on the same address is not
    expected to cause operational problems, but the option to disable
    COOKIE responses so that all servers have the same behavior is
    provided out of an abundance of caution. DNS COOKIE is an important
    security mechanism, and should not be disabled unless absolutely
    necessary.

    Remove support for silently ignoring 'no-change' deltas from BIND 8
    when processing an IXFR stream. 'no-change' deltas will now trigger a
    fallback to AXFR as the recovery mechanism.

    BIND 9 will no longer build on platforms that doesn't have proper IPv6
    support. BIND 9 now also requires non-broken POSIX-compatible pthread
    support. Such platforms are usually long after their end-of-life date
    and they are neither developed nor supported by their respective
    vendors.

    Support for DSA and DSA-NSEC3-SHA1 algorithms has been removed from
    BIND as the DSA key length is limited to 1024 bits and this is not
    considered secure enough.

    Support for RSAMD5 algorithm has been removed freom BIND as the usage
    of the RSAMD5 algorithm for DNSSEC has been deprecated in RFC6725 and
    the security of MD5 algorithm has been compromised and the its usage
    is considered harmful.

  * The incomplete support for internationalization message catalogs has
    been removed from BIND. Since the internationalization was never
    completed, and no localized message catalogs were ever made available
    for the portions of BIND in which they could have been used, this
    change will have no effect except to simplify the source code. BIND's
    log messages and other output were already only available in English.

Feature Changes

  * BIND will now always use the best CSPRNG (cryptographically-secure
    pseudo-random number generator) available on the platform where it is
    compiled. It will use arc4random() family of functions on BSD
    operating systems, getrandom() on Linux and Solaris, CryptGenRandom on
    Windows, and the selected cryptography provider library (OpenSSL or
    PKCS#11) as the last resort. [GL #221]

  * The default setting for dnssec-validation is now auto, which activates
    DNSSEC validation using the IANA root key. (The default can be changed
    back to yes, which activates DNSSEC validation only when keys are
    explicitly configured in named.conf, by building BIND with configure
    --disable-auto-validation.) [GL #30]

  * BIND can no longer be built without DNSSEC support. A cryptography
    provider (i.e., OpenSSL or a hardware service module with PKCS#11
    support) must be available. [GL #244]

  * Zone types primary and secondary are now available as synonyms for
    master and slave, respectively, in named.conf.

  * named will now log a warning if the old root DNSSEC key is explicitly
    configured and has not been updated. [RT #43670]

  * dig +nssearch will now list name servers that have timed out, in
    addition to those that respond. [GL #64]

  * Up to 64 response-policy zones are now supported by default;
    previously the limit was 32. [GL #123]

  * Several configuration options for time periods can now use TTL value
    suffixes (for example, 2h or 1d) in addition to an integer number of
    seconds. These include fstrm-set-reopen-interval, interface-interval,
    max-cache-ttl, max-ncache-ttl, max-policy-ttl, and min-update-interval
    . [GL #203]

  * NSID logging (enabled by the request-nsid option) now has its own nsid
    category, instead of using the resolver category.

  * The rndc nta command could not differentiate between views of the same
    name but different class; this has been corrected with the addition of
    a -class option. [GL #105]

  * allow-recursion-on and allow-query-cache-on each now default to the
    other if only one of them is set, in order to be consistent with the
    way allow-recursion and allow-query-cache work. [GL #319]

  * When compiled with IDN support, the dig and nslookup commands now
    disable IDN processing when the standard output is not a TTY (i.e.,
    when the output is not being read by a human). When running from a
    shell script, the command line options +idnin and +idnout may be used
    to enable IDN processing of input and output domain names,
    respectively. When running on a TTY, the +noidnin and +noidnout
    options may be used to disable IDN processing of input and output
    domain names.

  * The configuration option max-ncache-ttl cannot exceed seven days.
    Previously, larger values than this were silently lowered; now, they
    trigger a configuration error.

  * The new dig -r command line option disables reading of the file $HOME
    /.digrc.

  * Zone signing and key maintenance events are now logged to the dnssec
    category rather than zone.

Bug Fixes

  * Running rndc reconfig could cause inline-signing zones to stop
    signing. [GL #439]

  * Reloading all zones caused zone maintenance to stop for inline-signing
    zones. [GL #435]

  * Signatures loaded from the journal for the signed version of an
    inline-signing zone were not scheduled for refresh. [GL #482]

  * A referral response with a non-empty ANSWER section was incorrectly
    treated as an error; this caused certain domains to be non-resolvable.
    [GL #390]

  * When a negative trust anchor was added to multiple views using rndc
    nta, the text returned via rndc was incorrectly truncated after the
    first line, making it appear that only one NTA had been added. This
    has been fixed. [GL #105]

  * The view name is now included in the output of rndc nta -dump, for
    consistency with other options. [GL !816]

  * named now rejects excessively large incremental (IXFR) zone transfers
    in order to prevent possible corruption of journal files which could
    cause named to abort when loading zones. [GL #339]

License

BIND is open source software licenced 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 9.13 is an unstable development branch. When its development is
complete, it will be renamed to BIND 9.14, which will be a stable branch.

The end of life date for BIND 9.14 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://www.isc.org/downloads/software-support-policy/ 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 http://
www.isc.org/donate/.