BIND 9

Contents

 1. Introduction
 2. Reporting bugs and getting help
 3. Contributing to BIND
 4. BIND 9.10 features
 5. Building BIND
 6. macOS
 7. Compile-time options
 8. Automated testing
 9. Documentation
10. Change log
11. 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 is 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 licenced under the terms of the ISC License for all
versions up to and including BIND 9.10, and the Mozilla Public License
version 2.0 for all subsequent verisons.

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 release notes and errata, see http://www.isc.org/software/
bind9/releasenotes

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, please send mail to security-officer@isc.org.

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: doc/dev/contrib.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 9.10 features

BIND 9.10.0 includes a number of changes from BIND 9.9 and earlier
releases. New features include:

  * DNS Response-rate limiting (DNS RRL), which blunts the impact of
    reflection and amplification attacks, is always compiled in and no
    longer requires a compile-time option to enable it.
  * An experimental "Source Identity Token" (SIT) EDNS option is now
    available. Similar to DNS Cookies as invented by Donald Eastlake 3rd,
    these are designed to enable clients to detect off-path spoofed
    responses, and to enable servers to detect spoofed-source queries.
    Servers can be configured to send smaller responses to clients that
    have not identified themselves using a SIT option, reducing the
    effectiveness of amplification attacks. RRL processing has also been
    updated; clients proven to be legitimate via SIT are not subject to
    rate limiting. Use configure --enable-sit to enable this feature in
    BIND.
  * A new zone file format, map, stores zone data in a format that can be
    mapped directly into memory, allowing significantly faster zone
    loading.
  * delv (domain entity lookup and validation) is a new tool with dig-like
    semantics for looking up DNS data and performing internal DNSSEC
    validation. This allows easy validation in environments where the
    resolver may not be trustworthy, and assists with troubleshooting of
    DNSSEC problems. (NOTE: In previous development releases of BIND 9.10,
    this utility was called delve. The spelling has been changed to avoid
    confusion with the delve utility included with the Xapian search
    engine.)
  * Improved EDNS(0) processing for better resolver performance and
    reliability over slow or lossy connections.
  * A new configure --with-tuning=large option tunes certain compiled-in
    constants and default settings to values better suited to large
    servers with abundant memory. This can improve performance on such
    servers, but will consume more memory and may degrade performance on
    smaller systems.
  * Substantial improvement in response-policy zone (RPZ) performance. Up
    to 32 response-policy zones can be configured with minimal performance
    loss.
  * To improve recursive resolver performance, cache records which are
    still being requested by clients can now be automatically refreshed
    from the authoritative server before they expire, reducing or
    eliminating the time window in which no answer is available in the
    cache.
  * New rpz-client-ip triggers and drop policies allowing response
    policies based on the IP address of the client.
  * ACLs can now be specified based on geographic location using the
    MaxMind GeoIP databases. Use configure --with-geoip to enable.
  * Zone data can now be shared between views, allowing multiple views to
    serve the same zones authoritatively without storing multiple copies
    in memory.
  * New XML schema (version 3) for the statistics channel includes many
    new statistics and uses a flattened XML tree for faster parsing. The
    older schema is now deprecated.
  * A new stylesheet, based on the Google Charts API, displays XML
    statistics in charts and graphs on javascript-enabled browsers.
  * The statistics channel can now provide data in JSON format as well as
    XML.
  * New stats counters track TCP and UDP queries received per zone, and
    EDNS options received in total.
  * The internal and export versions of the BIND libraries (libisc,
    libdns, etc) have been unified so that external library clients can
    use the same libraries as BIND itself.
  * A new compile-time option, configure --enable-native-pkcs11, allows
    BIND 9 cryptography functions to use the PKCS#11 API natively, so that
    BIND can drive a cryptographic hardware service module (HSM) directly
    instead of using a modified OpenSSL as an intermediary. (Note: This
    feature requires an HSM to have a full implementation of the PKCS#11
    API; many current HSMs only have partial implementations. The new
    pkcs11-tokens command can be used to check API completeness. Native
    PKCS#11 is known to work with the Thales nShield HSM and with SoftHSM
    version 2 from the Open DNSSEC project.)
  * The new max-zone-ttl option enforces maximum TTLs for zones. This can
    simplify the process of rolling DNSSEC keys by guaranteeing that
    cached signatures will have expired within the specified amount of
    time.
  * dig +subnet sends an EDNS CLIENT-SUBNET option when querying.
  * dig +expire sends an EDNS EXPIRE option when querying. When this
    option is sent with an SOA query to a server that supports it, it will
    report the expiry time of a slave zone.
  * New dnssec-coverage tool to check DNSSEC key coverage for a zone and
    report if a lapse in signing coverage has been inadvertently
    scheduled.
  * Signing algorithm flexibility and other improvements for the rndc
    control channel.
  * named-checkzone and named-compilezone can now read journal files,
    allowing them to process dynamic zones.
  * Multiple DLZ databases can now be configured. Individual zones can be
    configured to be served from a specific DLZ database. DLZ databases
    now serve zones of type master and redirect.
  * rndc zonestatus reports information about a specified zone.
  * named now listens on IPv6 as well as IPv4 interfaces by default.
  * named now preserves the capitalization of names when responding to
    queries: for instance, a query for "example.com" may be answered with
    "example.COM" if the name was configured that way in the zone file.
    Some clients have a bug causing them to depend on the older behavior,
    in which the case of the answer always matched the case of the query,
    rather than the case of the name configured in the DNS. Such clients
    can now be specified in the new no-case-compress ACL; this will
    restore the older behavior of named for those clients only.
  * new dnssec-importkey command allows the use of offline DNSSEC keys
    with automatic DNSKEY management.
  * New named-rrchecker tool to verify the syntactic correctness of
    individual resource records.
  * When re-signing a zone, the new dnssec-signzone -Q option drops
    signatures from keys that are still published but are no longer
    active.
  * named-checkconf -px will print the contents of configuration files
    with the shared secrets obscured, making it easier to share
    configuration (e.g. when submitting a bug report) without revealing
    private information.
  * rndc scan causes named to re-scan network interfaces for changes in
    local addresses.
  * On operating systems with support for routing sockets, network
    interfaces are re-scanned automatically whenever they change.
  * tsig-keygen is now available as an alternate command name to use for
    ddns-confgen.

BIND 9.10.1

BIND 9.10.1 is a maintenance release, and addresses the security flaws
described in CVE-2014-3214 and CVE-2014-3859.

BIND 9.10.2

BIND 9.10.2 is a maintenance release, and addresses the security flaws
described in CVE-2014-8500, CVE-2014-8680 and CVE-2015-1349.

BIND 9.10.3

BIND 9.10.3 is a maintenance release, and addresses the security flaws
described in CVE-2015-4620, CVE-2015-5477, CVE-2015-5722, and
CVE-2015-5986.

It also makes the following new features available:

  * New "fetchlimit" quotas are now available for the use of recursive
    resolvers that are are under high query load for domains whose
    authoritative servers are nonresponsive or are experiencing a denial
    of service attack.

      + fetches-per-server 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
        fetch-quota-params option.
      + fetches-per-zone 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.)
      + New stats counters have been added to count queries spilled due to
        these quotas.

NOTE: These features are NOT built in by default; use configure
--enable-fetchlimit to enable them.

  * dig now supports sending of arbitrary EDNS options by specifying them
    on the command line.

BIND 9.10.4

BIND 9.10.4 is a maintenance release, and addresses the security flaws
described in CVE-2015-8000, CVE-2015-8461, CVE-2015-8704, CVE-2015-8705,
CVE-2016-1285, CVE-2016-1286, CVE-2016-2088, CVE-2016-2775 and
CVE-2016-2776.

BIND 9.10.5

BIND 9.10.5 is a maintenance release, and addresses the security flaws
disclosed in CVE-2016-2775, CVE-2016-2776, CVE-2016-6170, CVE-2016-8864,
CVE-2016-9131, CVE-2016-9147, CVE-2016-9444, CVE-2017-3135, CVE-2017-3136,
CVE-2017-3137, and CVE-2017-3138.

BIND 9.10.6

BIND 9.10.6 is a maintenance release, and addresses the security flaws
disclosed in CVE-2017-3140 and CVE-2017-3141, CVE-2017-3142 and
CVE-2017-3143.

BIND 9.10.7

BIND 9.10.7 is a maintenance release, and addresses the security flaw
disclosed in CVE-2017-3145.

BIND 9.10.8

BIND 9.10.8 is a maintenance release, and addresses the security flaw
disclosed in CVE-2018-5738.

Building BIND

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 RedHat, Fedora, Debian,
Ubuntu, SuSE, Slackware, FreeBSD, NetBSD, OpenBSD, Mac OS X, Solaris,
HP-UX, AIX, SCO OpenServer, and OpenWRT.

BIND is also available for Windows XP, 2003, 2008, and higher. See
win32utils/readme1st.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:

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   Optional, used for cross-compiling
BUILD_CPPFLAGS
BUILD_LDFLAGS
BUILD_LIBS

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".
This will add /usr/include to the system and install the compiler and
other tools so that they can be easily found.

Compile-time options

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

On most platforms, BIND 9 is built with multithreading support, allowing
it to take advantage of multiple CPUs. You can configure this by
specifying --enable-threads or --disable-threads on the configure command
line. The default is to enable threads, except on some older operating
systems on which threads are known to have had problems in the past.
(Note: Prior to BIND 9.10, the default was to disable threads on Linux
systems; this has now been reversed. On Linux systems, the threaded build
is known to change BIND's behavior with respect to file permissions; it
may be necessary to specify a user with the -u option when running named.)

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

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.

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: libxml2 http://xmlsoft.org or json-c https://
github.com/json-c. If these are installed at a nonstandard location,
specify the prefix using --with-libxml2=/prefix or --with-libjson=/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, use
specify the prefix using "--with-geoip=/prefix".

Portions of BIND that are written in Python, including dnssec-coverage,
dnssec-checkds, and some of the system tests, require the 'argparse'
module to be available. 'argparse' is a standard module as of Python 2.7
and Python 3.2.

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.

If your operating system has integrated support for IPv6, it will be used
automatically. If you have installed KAME IPv6 separately, use --with-kame
[=PATH] to specify its location.

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 Automated Testing Framework (ATF). To run
them, use configure --with-atf, then run 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.

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)
