README

BIND 9

Contents

 1. Introduction
 2. Reporting bugs and getting help
 3. Contributing to BIND
 4. BIND 9.14 features
 5. Building BIND
 6. macOS
 7. Dependencies
 8. Compile-time options
 9. Automated testing
10. Documentation
11. Change log
12. Acknowledgments

Introduction

BIND (Berkeley Internet Name Domain) is a complete, highly portable
implementation of the DNS (Domain Name System) protocol.

The BIND name server, named, is able to serve as an authoritative name
server, recursive resolver, DNS forwarder, or all three simultaneously. It
implements views for split-horizon DNS, automatic DNSSEC zone signing and
key management, catalog zones to facilitate provisioning of zone data
throughout a name server constellation, response policy zones (RPZ) to
protect clients from malicious data, response rate limiting (RRL) and
recursive query limits to reduce distributed denial of service attacks,
and many other advanced DNS features. BIND also includes a suite of
administrative tools, including the dig and delv DNS lookup tools,
nsupdate for dynamic DNS zone updates, rndc for remote name server
administration, and more.

BIND 9 began as a complete re-write of the BIND architecture that was used
in versions 4 and 8. Internet Systems Consortium (https://www.isc.org), a
501(c)(3) public benefit corporation dedicated to providing software and
services in support of the Internet infrastructure, developed BIND 9 and
is responsible for its ongoing maintenance and improvement. BIND is open
source software licensed under the terms of the Mozilla Public License,
version 2.0.

For a summary of features introduced in past major releases of BIND, see
the file HISTORY.

For a detailed list of changes made throughout the history of BIND 9, see
the file CHANGES. See below for details on the CHANGES file format.

For up-to-date versions and release notes, see https://www.isc.org/
download/.

For information about supported platforms, see PLATFORMS.

Reporting bugs and getting help

To report non-security-sensitive bugs or request new features, you may
open an Issue in the BIND 9 project on the ISC GitLab server at https://
gitlab.isc.org/isc-projects/bind9.

Please note that, unless you explicitly mark the newly created Issue as
"confidential", it will be publicly readable. Please do not include any
information in bug reports that you consider to be confidential unless the
issue has been marked as such. In particular, if submitting the contents
of your configuration file in a non-confidential Issue, it is advisable to
obscure key secrets: this can be done automatically by using
named-checkconf -px.

If the bug you are reporting is a potential security issue, such as an
assertion failure or other crash in named, please do NOT use GitLab to
report it. Instead, send mail to security-officer@isc.org using our
OpenPGP key to secure your message. (Information about OpenPGP and links
to our key can be found at https://www.isc.org/pgpkey.) Please do not
discuss the bug on any public mailing list.

For a general overview of ISC security policies, read the Knowledge Base
article at https://kb.isc.org/docs/aa-00861.

Professional support and training for BIND are available from ISC at
https://www.isc.org/support.

To join the BIND Users mailing list, or view the archives, visit https://
lists.isc.org/mailman/listinfo/bind-users.

If you're planning on making changes to the BIND 9 source code, you may
also want to join the BIND Workers mailing list, at https://lists.isc.org/
mailman/listinfo/bind-workers.

Contributing to BIND

ISC maintains a public git repository for BIND; details can be found at
http://www.isc.org/git/.

Information for BIND contributors can be found in the following files: -
General information: CONTRIBUTING.md - BIND 9 code style: doc/dev/style.md
- BIND architecture and developer guide: doc/dev/dev.md

Patches for BIND may be submitted as merge requests in the ISC GitLab
server at at https://gitlab.isc.org/isc-projects/bind9/merge_requests.

By default, external contributors don't have ability to fork BIND in the
GitLab server, but if you wish to contribute code to BIND, you may request
permission to do so. Thereafter, you can create git branches and directly
submit requests that they be reviewed and merged.

If you prefer, you may also submit code by opening a GitLab Issue and
including your patch as an attachment, preferably generated by git
format-patch.

BIND 9.14 features

BIND 9.14.0 is the first release from a new stable branch of BIND 9,
incorporating all changes from the 9.13 development branch, updating the
most recent stable branch, 9.12. These changes include:

  * A new "plugin" mechanism has been added to allow query functionality
    to be extended using dynamically loadable libraries. The "filter-aaaa"
    feature has been removed from named and is now implemented as a
    plugin.
  * QNAME minimization, as described in RFC 7816, is now supported.
  * Socket and task code has been refactored to improve performance on
    most modern machines.
  * "Root key sentinel" support, enabling validating resolvers to indicate
    via a special query which trust anchors are configured for the root
    zone.
  * Secondary zones can now be configured as "mirror" zones; their
    contents are transferred in as with traditional slave zones, but are
    subject to DNSSEC validation and are not treated as authoritative data
    when answering. This makes it easier to configure a local copy of the
    root zone as described in RFC 7706.
  * The "validate-except" option allows configuration of domains below
    which DNSSEC validation should not be performed.
  * The default value of "dnssec-validation" is now "auto".
  * IDNA2008 is now supported when linking with libidn2.
  * "named -V" now outputs the default paths for files used by named and
    other tools.

In addition, workarounds that were formerly in place to enable resolution
of domains whose authoritative servers did not respond to EDNS queries
have been removed. See https://dnsflagday.net for more details.

Cryptographic support has been modernized. BIND now uses the best
available pseudo-random number generator for the platform on which it's
built. Very old versions of OpenSSL are no longer supported. Cryptography
is now mandatory: building BIND without DNSSEC is no longer supported.

Special code to support certain legacy operating systems has also been
removed; see the file PLATFORMS.md for details of supported platforms. In
addition to OpenSSL, BIND now requires support for IPv6, threads, and
standard atomic operations provided by the C compiler. Non-threaded builds
are no longer supported.

BIND 9.14.1

BIND 9.14.1 is a maintenance release, and addresses security
vulnerabilities disclosed in CVE-2018-5743 and CVE-2019-6467.

BIND 9.14.2

BIND 9.14.2 is a maintenance release.

BIND 9.14.3

BIND 9.14.3 is a maintenance release, and addresses the security
vulnerability disclosed in CVE-2019-6471.

BIND 9.14.4

BIND 9.14.4 is a maintenance release, and also adds support for the new
MaxMind GeoIP2 geolocation API when built with configure --with-geoip2.

BIND 9.14.5

BIND 9.14.5 is a maintenance release.

BIND 9.14.6

BIND 9.14.6 is a maintenance release.

BIND 9.14.7

BIND 9.14.7 is a maintenance release, and also addresses the security
vulnerabilities disclosed in CVE-2019-6475 and CVE-2019-6476.

BIND 9.14.8

BIND 9.14.8 is a maintenance release, and also addresses the security
vulnerability disclosed in CVE-2019-6477.

BIND 9.14.9

BIND 9.14.9 is a maintenance release.

BIND 9.14.10

BIND 9.14.10 is a maintenance release.

BIND 9.14.11

BIND 9.14.11 is a maintenance release.

Building BIND

Minimally, BIND requires a UNIX or Linux system with an ANSI C compiler,
basic POSIX support, and a 64-bit integer type. Successful builds have
been observed on many versions of Linux and UNIX, including RHEL/CentOS,
Fedora, Debian, Ubuntu, SLES, openSUSE, Slackware, Alpine, FreeBSD,
NetBSD, OpenBSD, macOS, Solaris, OpenIndiana, OmniOS CE, HP-UX, and
OpenWRT.

BIND requires a cryptography provider library such as OpenSSL or a
hardware service module supporting PKCS#11. On Linux, BIND requires the
libcap library to set process privileges, though this requirement can be
overridden by disabling capability support at compile time. See
Compile-time options below for details on other libraries that may be
required to support optional features.

BIND is also available for Windows Server 2008 and higher. See win32utils/
build.txt for details on building for Windows systems.

To build on a UNIX or Linux system, use:

    $ ./configure
    $ make

If you're planning on making changes to the BIND 9 source, you should run
make depend. If you're using Emacs, you might find make tags helpful.

Several environment variables that can be set before running configure
will affect compilation. Significant ones are:

   Variable                            Description
CC             The C compiler to use. configure tries to figure out the
               right one for supported systems.
               C compiler flags. Defaults to include -g and/or -O2 as
CFLAGS         supported by the compiler. Please include '-g' if you need
               to set CFLAGS.
               System header file directories. Can be used to specify
STD_CINCLUDES  where add-on thread or IPv6 support is, for example.
               Defaults to empty string.
               Any additional preprocessor symbols you want defined.
STD_CDEFINES   Defaults to empty string. For a list of possible settings,
               see the file OPTIONS.
LDFLAGS        Linker flags. Defaults to empty string.
BUILD_CC       Needed when cross-compiling: the native C compiler to use
               when building for the target system.
BUILD_CFLAGS   CFLAGS for the target system during cross-compiling.
BUILD_CPPFLAGS CPPFLAGS for the target system during cross-compiling.
BUILD_LDFLAGS  LDFLAGS for the target system during cross-compiling.
BUILD_LIBS     LIBS for the target system during cross-compiling.

Additional environment variables affecting the build are listed at the end
of the configure help text, which can be obtained by running the command:

$ ./configure --help

macOS

Building on macOS assumes that the "Command Tools for Xcode" is installed.
This can be downloaded from https://developer.apple.com/download/more/ or,
if you have Xcode already installed, you can run xcode-select --install.
(Note that an Apple ID may be required to access the download page.)

Dependencies

Portions of BIND that are written in Python, including dnssec-keymgr,
dnssec-coverage, dnssec-checkds, and some of the system tests, require the
argparse, ply and distutils.core modules to be available. argparse is a
standard module as of Python 2.7 and Python 3.2. ply is available from
https://pypi.python.org/pypi/ply. distutils.core is required for
installation.

Compile-time options

To see a full list of configuration options, run configure --help.

To build shared libraries, specify --with-libtool on the configure command
line.

For the server to support DNSSEC, you need to build it with crypto
support. To use OpenSSL, you should have OpenSSL 1.0.2e or newer
installed. If the OpenSSL library is installed in a nonstandard location,
specify the prefix using --with-openssl=<PREFIX> on the configure command
line. To use a PKCS#11 hardware service module for cryptographic
operations, specify the path to the PKCS#11 provider library using
--with-pkcs11=<PREFIX>, and configure BIND with --enable-native-pkcs11.

To support the HTTP statistics channel, the server must be linked with at
least one of the following libraries: libxml2 http://xmlsoft.org or json-c
https://github.com/json-c/json-c. If these are installed at a nonstandard
location, then:

  * for libxml2, specify the prefix using --with-libxml2=/prefix,
  * for json-c, adjust PKG_CONFIG_PATH.

To support compression on the HTTP statistics channel, the server must be
linked against libzlib. If this is installed in a nonstandard location,
specify the prefix using --with-zlib=/prefix.

To support storing configuration data for runtime-added zones in an LMDB
database, the server must be linked with liblmdb. If this is installed in
a nonstandard location, specify the prefix using with-lmdb=/prefix.

To support GeoIP location-based ACLs, the server must be linked with
libGeoIP. This is not turned on by default; BIND must be configured with
--with-geoip. If the library is installed in a nonstandard location,
specify the prefix using --with-geoip=/prefix.

For DNSTAP packet logging, you must have installed libfstrm https://
github.com/farsightsec/fstrm and libprotobuf-c https://
developers.google.com/protocol-buffers, and BIND must be configured with
--enable-dnstap.

Certain compiled-in constants and default settings can be increased to
values better suited to large servers with abundant memory resources (e.g,
64-bit servers with 12G or more of memory) by specifying --with-tuning=
large on the configure command line. This can improve performance on big
servers, but will consume more memory and may degrade performance on
smaller systems.

On Linux, process capabilities are managed in user space using the libcap
library, which can be installed on most Linux systems via the libcap-dev
or libcap-devel package. Process capability support can also be disabled
by configuring with --disable-linux-caps.

On some platforms it is necessary to explicitly request large file support
to handle files bigger than 2GB. This can be done by using
--enable-largefile on the configure command line.

Support for the "fixed" rrset-order option can be enabled or disabled by
specifying --enable-fixed-rrset or --disable-fixed-rrset on the configure
command line. By default, fixed rrset-order is disabled to reduce memory
footprint.

The --enable-querytrace option causes named to log every step of
processing every query. This should only be enabled when debugging,
because it has a significant negative impact on query performance.

make install will install named and the various BIND 9 libraries. By
default, installation is into /usr/local, but this can be changed with the
--prefix option when running configure.

You may specify the option --sysconfdir to set the directory where
configuration files like named.conf go by default, and --localstatedir to
set the default parent directory of run/named.pid. For backwards
compatibility with BIND 8, --sysconfdir defaults to /etc and
--localstatedir defaults to /var if no --prefix option is given. If there
is a --prefix option, sysconfdir defaults to $prefix/etc and localstatedir
defaults to $prefix/var.

Automated testing

A system test suite can be run with make test. The system tests require
you to configure a set of virtual IP addresses on your system (this allows
multiple servers to run locally and communicate with one another). These
IP addresses can be configured by running the command bin/tests/system/
ifconfig.sh up as root.

Some tests require Perl and the Net::DNS and/or IO::Socket::INET6 modules,
and will be skipped if these are not available. Some tests require Python
and the dnspython module and will be skipped if these are not available.
See bin/tests/system/README for further details.

Unit tests are implemented using the CMocka unit testing framework. To
build them, use configure --with-cmocka. Execution of tests is done by the
Kyua test execution engine; if the kyua command is available, then unit
tests can be run via make test or make unit.

Documentation

The BIND 9 Administrator Reference Manual is included with the source
distribution, in DocBook XML, HTML, and PDF format, in the doc/arm
directory.

Some of the programs in the BIND 9 distribution have man pages in their
directories. In particular, the command line options of named are
documented in bin/named/named.8.

Frequently (and not-so-frequently) asked questions and their answers can
be found in the ISC Knowledge Base at https://kb.isc.org.

Additional information on various subjects can be found in other README
files throughout the source tree.

Change log

A detailed list of all changes that have been made throughout the
development BIND 9 is included in the file CHANGES, with the most recent
changes listed first. Change notes include tags indicating the category of
the change that was made; these categories are:

   Category                            Description
[func]         New feature
[bug]          General bug fix
[security]     Fix for a significant security flaw
[experimental] Used for new features when the syntax or other aspects of
               the design are still in flux and may change
[port]         Portability enhancement
[maint]        Updates to built-in data such as root server addresses and
               keys
[tuning]       Changes to built-in configuration defaults and constants to
               improve performance
[performance]  Other changes to improve server performance
[protocol]     Updates to the DNS protocol such as new RR types
[test]         Changes to the automatic tests, not affecting server
               functionality
[cleanup]      Minor corrections and refactoring
[doc]          Documentation
[contrib]      Changes to the contributed tools and libraries in the
               'contrib' subdirectory
               Used in the master development branch to reserve change
[placeholder]  numbers for use in other branches, e.g. when fixing a bug
               that only exists in older releases

In general, [func] and [experimental] tags will only appear in new-feature
releases (i.e., those with version numbers ending in zero). Some new
functionality may be backported to older releases on a case-by-case basis.
All other change types may be applied to all currently-supported releases.

Bug report identifiers

Most notes in the CHANGES file include a reference to a bug report or
issue number. Prior to 2018, these were usually of the form [RT #NNN] and
referred to entries in the "bind9-bugs" RT database, which was not open to
the public. More recent entries use the form [GL #NNN] or, less often, [GL
!NNN], which, respectively, refer to issues or merge requests in the
GitLab database. Most of these are publicly readable, unless they include
information which is confidential or security sensitive.

To look up a GitLab issue by its number, use the URL https://
gitlab.isc.org/isc-projects/bind9/issues/NNN. To look up a merge request,
use https://gitlab.isc.org/isc-projects/bind9/merge_requests/NNN.

In rare cases, an issue or merge request number may be followed with the
letter "P". This indicates that the information is in the private ISC
GitLab instance, which is not visible to the public.

Acknowledgments

  * The original development of BIND 9 was underwritten by the following
    organizations:

      Sun Microsystems, Inc.
      Hewlett Packard
      Compaq Computer Corporation
      IBM
      Process Software Corporation
      Silicon Graphics, Inc.
      Network Associates, Inc.
      U.S. Defense Information Systems Agency
      USENIX Association
      Stichting NLnet - NLnet Foundation
      Nominum, Inc.

  * This product includes software developed by the OpenSSL Project for
    use in the OpenSSL Toolkit. http://www.OpenSSL.org/

  * This product includes cryptographic software written by Eric Young
    (eay@cryptsoft.com)

  * This product includes software written by Tim Hudson
    (tjh@cryptsoft.com)
