Release Notes for BIND Version 9.17.0

Introduction

BIND 9.17 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 9.18 release, this document will be updated with additional features
added and bugs fixed.

Please see the file CHANGES for a more detailed list of changes and bug
fixes.

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 libuv asynchronous I/O library and the OpenSSL cryptography library
must be available for the target platform. A PKCS#11 provider can be used
instead of OpenSSL 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 9.17.0

Known Issues

  * UDP network ports used for listening can no longer simultaneously be
    used for sending traffic. An example configuration which triggers this
    issue would be one which uses the same address:port pair for listen-on
    (-v6) statements as for notify-source(-v6) or transfer-source(-v6).
    While this issue affects all operating systems, it only triggers log
    messages (e.g. "unable to create dispatch for reserved port") on some
    of them. There are currently no plans to make such a combination of
    settings work again.

New Features

  * When a secondary server receives a large incremental zone transfer
    (IXFR), it can have a negative impact on query performance while the
    incremental changes are applied to the zone. To address this, named
    can now limit the size of IXFR responses it sends in response to zone
    transfer requests. If an IXFR response would be larger than an AXFR of
    the entire zone, it will send an AXFR response instead.

    This behavior is controlled by the max-ixfr-ratio option - a
    percentage value representing the ratio of IXFR size to the size of a
    full zone transfer. The default is 100%. [GL #1515]

Feature Changes

  * The system-provided POSIX Threads read-write lock implementation is
    now used by default instead of the native BIND 9 implementation.
    Please be aware that glibc versions 2.26 through 2.29 had a bug that
    could cause BIND 9 to deadlock. A fix was released in glibc 2.30, and
    most current Linux distributions have patched or updated glibc, with
    the notable exception of Ubuntu 18.04 (Bionic) which is a work in
    progress. If you are running on an affected operating system, compile
    BIND 9 with --disable-pthread-rwlock until a fixed version of glibc is
    available. [GL !3125]

  * The rndc nta -dump and rndc secroots commands now both include
    validate-except entries when listing negative trust anchors. These are
    indicated by the keyword permanent in place of the expiry date. [GL
    #1532]

Bug Fixes

  * Fixed re-signing issues with inline zones which resulted in records
    being re-signed late or not at all.

License

BIND 9 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/contact/.

End of Life

BIND 9.17 is an unstable development branch. When its development is
complete, it will be renamed to BIND 9.18, which will be a stable branch.

The end of life date for BIND 9.18 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.
