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
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 licensed under the terms of ISC License for all versions up to and including BIND 9.10, and the Mozilla Public License version 2.0 for all subsequent versions.
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/.
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
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 firstname.lastname@example.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.
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
BIND 9.11.0 includes a number of changes from BIND 9.10 and earlier releases. New features include:
fetches-per-serverlimits 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-zonelimits 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.)
dnssec-keymgrkey maintenance utility, which can generate or update keys as needed to ensure that a zone’s keys match a defined DNSSEC policy.
nsip-wait-recurseswitch to RPZ. This causes NSIP rules to be skipped if a name server IP address isn’t in the cache yet; the address will be looked up and the rule will be applied on future queries.
controlsblock in named.conf can now grant read-only
rndcaccess to specified clients or keys. Read-only clients could, for example, check
rndc statusbut could not reconfigure or shut down the server.
rndccommands can now return arbitrarily large amounts of text to the caller.
rndc signing -serial <number> <zonename>. This allows inline-signing zones to be set to a specific serial number.
rndc ntacommand can be used to set a Negative Trust Anchor (NTA), disabling DNSSEC validation for a specific domain; this can be used when responses from a domain are known to be failing validation due to administrative error rather than because of a spoofing attack. Negative trust anchors are strictly temporary; by default they expire after one hour, but can be configured to last up to one week.
rndc delzonecan now be used on zones that were not originally created by “rndc addzone”.
rndc modzonereconfigures a single zone, without requiring the entire server to be reconfigured.
rndc showzonedisplays the current configuration of a zone.
rndc managed-keyscan be used to check the status of RFC 5001 managed trust anchors, or to force trust anchors to be refreshed.
max-cache-sizecan now be set to a percentage of available memory. The default is 90%.
ecselements can match against the the address encoded in the option. This can be used to select a view for a query, so that different answers can be provided depending on the client network.
dnssec-keyfromlabel) now take
-Dsyncoptions to set the publication and deletion times of CDS and CDNSKEY parent-synchronization records. Both
dnssec-signzonecan now publish and remove these records at the scheduled times.
minimal-anyoption reduces the size of UDP responses for query type ANY by returning a single arbitrarily selected RRset instead of all RRsets.
masterfile-stylezone option controls the formatting of text zone files: When set to
full, a zone file is dumped in single-line-per-record format.
serial-update-methodcan now be set to
date. On update, the serial number will be set to the current date in YYYYMMDDNN format.
dnssec-signzone -N datesets the serial number to YYYYMMDDNN.
named -L <filename>causes named to send log messages to the specified file by default instead of to the system log.
dig +ttlunitsprints TTL values with time-unit suffixes: w, d, h, m, s for weeks, days, hours, minutes, and seconds.
dig +unknownformatprints dig output in RFC 3597 “unknown record” presentation format.
dig +ednsoptallows dig to set arbitrary EDNS options on requests.
dig +ednsflagsallows dig to set yet-to-be-defined EDNS flags on requests.
mdigis an alternate version of dig which sends multiple pipelined TCP queries to a server. Instead of waiting for a response after sending a query, it sends all queries immediately and displays responses in the order received.
serial-query-rateno longer controls NOTIFY messages. These are separately controlled by
check-namesprocessing by default on records to be added. This can be disabled with
nxdomain-redirect) has been added, allowing redirection to a specified DNS namespace instead of a single redirect zone.
nzffiles, are now named after their corresponding views unless the view name contains characters incompatible with use as a filename. Old style filenames (based on the hash of the view name) will still work.
BIND 9.11.1 is a maintenance release, and addresses the security flaws disclosed in CVE-2016-6170, CVE-2016-8864, CVE-2016-9131, CVE-2016-9147, CVE-2016-9444, CVE-2016-9778, CVE-2017-3135, CVE-2017-3136, CVE-2017-3137 and CVE-2017-3138.
BIND 9.11.2 is a maintenance release, and addresses the security flaws disclosed in CVE-2017-3140, CVE-2017-3141, CVE-2017-3142 and CVE-2017-3143. It also addresses several bugs related to the use of an LMDB database to store data related to zones added via
rndc addzone or catalog zones.
BIND 9.11.3 is a maintenance release, and addresses the security flaw disclosed in CVE-2017-3145.
BIND 9.11.4 is a maintenance release, and addresses the security flaw disclosed in CVE-2018-5738. It also introduces “root key sentinel” support, enabling validating resolvers to indicate via a special query which trust anchors are configured for the root zone.
BIND 9.11.5 is a maintenance release, and also addresses CVE-2018-5741 by correcting faulty documentation and introducing the following new feature:
ms-selfsubrule types for
update-policystatements allow updating of subdomains based on a Kerberos or Active Directory machine principal.
BIND 9.11.6 is a maintenance release, and also addresses the security flaws disclosed in CVE-2018-5743, CVE-2018-5745, CVE-2018-5744, and CVE-2019-6465.
BIND 9.11.7 is a maintenance release, and also addresses the security flaw disclosed in CVE-2018-5743.
BIND 9.11.8 is a maintenance release, and also addresses the security flaw disclosed in CVE-2019-6471.
BIND 9.11.9 is a maintenance release, and also adds support for the new MaxMind GeoIP2 geolocation API when built with
BIND 9.11.10 is a maintenance release.
BIND 9.11.11 is a maintenance release.
BIND 9.11.12 is a maintenance release.
BIND 9.11.13 is a maintenance release, and also addresses the security vulnerability disclosed in CVE-2019-6477.
BIND 9.11.14 is a maintenance release.
BIND 9.11.15 is a maintenance release.
BIND 9.11.16 is a maintenance release.
BIND 9.11.17 is a maintenance release.
BIND 9.11.18 is a maintenance release.
BIND 9.11.19 is a maintenance release, and also addresses the security vulnerabilities disclosed in CVE-2020-8616 and CVE-2020-8617.
BIND 9.11.20 is a maintenance release, and also addresses the security vulnerability disclosed in CVE-2020-8619.
BIND 9.11.21 is a maintenance release.
BIND 9.11.22 is a maintenance release, and also addresses the security vulnerabilities disclosed in CVE-2020-8622, CVE-2020-8623, and CVE-2020-8624.
BIND 9.11.23 is a maintenance release.
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 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:
||The C compiler to use.
||C compiler flags. Defaults to include -g and/or -O2 as supported by the compiler. Please include ‘-g’ if you need to set
||System header file directories. Can be used to specify where add-on thread or IPv6 support is, for example. Defaults to empty string.|
||Any additional preprocessor symbols you want defined. Defaults to empty string. For a list of possible settings, see the file OPTIONS.|
||Linker flags. Defaults to empty string.|
||Needed when cross-compiling: the native C compiler to use when building for the target system.|
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
On platforms where neither the C11 Atomic operations library nor custom ISC atomic operations are available, updating the statistics counters is not locked due to performance reasons and therefore the counters might be inaccurate. Anybody building BIND 9 is strongly advised to use a modern C11 compiler with C11 Atomic operations library support.
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.)
Portions of BIND that are written in Python, including
dnssec-checkds, and some of the system tests, require the
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.
To see a full list of configuration options, run
On most platforms, BIND 9 is built with multithreading support, allowing it to take advantage of multiple CPUs. You can configure this by specifying
--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
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:
libxml2, specify the prefix using
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
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
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”.
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
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 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
--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.
--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
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
--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
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
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
The BIND 9 Administrator Reference Manual is included with the source distribution, in DocBook XML, HTML, and PDF format, in the
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
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.
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:
|[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|
|[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|
|[contrib]||Changes to the contributed tools and libraries in the ‘contrib’ subdirectory|
|[placeholder]||Used in the master development branch to reserve change 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.
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.
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 (email@example.com)
This product includes software written by Tim Hudson (firstname.lastname@example.org)