README revision 59663800d2ec04777dae2791dd92aa563faf94c8
BIND 9
Contents
1. Introduction
2. Reporting bugs and getting help
3. Contributing to BIND
4. BIND 9.11 features
5. Building BIND
6. Compile-time options
7. Automated testing
8. Documentation
9. Change log
10. 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 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 release notes and errata, see http://www.isc.org/software/
Reporting bugs and getting help
Please report assertion failure errors and suspected security issues to
security-officer@isc.org.
General bug reports can be sent to bind9-bugs@isc.org.
Feature requests can be sent to bind-suggest@isc.org.
Please note that, while ISC's ticketing system is not currently publicly
readable, this may change in the future. Please do not include information
in bug reports that you consider to be confidential. For example, when
sending the contents of your configuration file, it is advisable to
obscure key secrets; this can be done automatically by using
named-checkconf -px.
Professional support and training for BIND are available from ISC at
To join the BIND Users mailing list, or view the archives, visit https://
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/
Contributing to BIND
A public git repository for BIND is maintained at http://www.isc.org/git/,
and also on Github at https://github.com/isc-projects.
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 either as Github pull requests or via
email. When submitting a patch via email, please prepend the subject
header with "[PATCH]" so it will be easier for us to find. If your patch
introduces a new feature in BIND, please submit it to bind-suggest@isc.org
; if it fixes a bug, please submit it to bind9-bugs@isc.org.
BIND 9.11 features
BIND 9.11.0 includes a number of changes from BIND 9.10 and earlier
releases. New features include:
* Added support for Catalog Zones, a new method for provisioning
servers: a list of zones to be served is stored in a DNS zone, along
with their configuration parameters. Changes to the catalog zone are
propagated to slaves via normal AXFR/IXFR, whereupon the zones that
are listed in it are automatically added, deleted or reconfigured.
* Added support for "dnstap", a fast and flexible method of capturing
and logging DNS traffic.
* Added support for "dyndb", a new API for loading zone data from an
external database, developed by Red Hat for the FreeIPA project.
* "fetchlimit" quotas are now compiled in by default. These are 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.
* Added a new dnssec-keymgr key mainenance utility, which can generate
or update keys as needed to ensure that a zone's keys match a defined
DNSSEC policy.
* The experimental "SIT" feature in BIND 9.10 has been renamed "COOKIE"
and is no longer optional. EDNS COOKIE is a mechanism enabling clients
to detect off-path spoofed responses, and servers to detect
spoofed-source queries. Clients that identify themselves using COOKIE
options are not subject to response rate limiting (RRL) and can
receive larger UDP responses.
* SERVFAIL responses can now be cached for a limited time (defaulting to
1 second, with an upper limit of 30). This can reduce the frequency of
retries when a query is persistently failing.
* Added an nsip-wait-recurse switch 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.
* Added a Python RNDC module. This allows multiple commands to sent over
a persistent RNDC channel, which saves time.
* The controls block in named.conf can now grant read-only rndc access
to specified clients or keys. Read-only clients could, for example,
check rndc status but could not reconfigure or shut down the server.
* rndc commands can now return arbitrarily large amounts of text to the
caller.
* The zone serial number of a dynamically updatable zone can now be set
via rndc signing -serial <number> <zonename>. This allows
inline-signing zones to be set to a specific serial number.
* The new rndc nta command 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 delzone can now be used on zones that were not originally created
by "rndc addzone".
* rndc modzone reconfigures a single zone, without requiring the entire
server to be reconfigured.
* rndc showzone displays the current configuration of a zone.
* rndc managed-keys can be used to check the status of RFC 5001 managed
trust anchors, or to force trust anchors to be refreshed.
* max-cache-size can now be set to a percentage of available memory. The
default is 90%.
* Update forwarding performance has been improved by allowing a single
TCP connection to be shared by multiple updates.
* The EDNS Client Subnet (ECS) option is now supported for authoritative
servers; if a query contains an ECS option then ACLs containing geoip
or ecs elements 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.
* The EDNS EXPIRE option has been implemented on the client side,
allowing a slave server to set the expiration timer correctly when
transferring zone data from another slave server.
* The key generation and manipulation tools (dnssec-keygen,
dnssec-settime, dnssec-importkey, dnssec-keyfromlabel) now take -Psync
and -Dsync options to set the publication and deletion times of CDS
and CDNSKEY parent-synchronization records. Both named and
dnssec-signzone can now publish and remove these records at the
scheduled times.
* A new minimal-any option reduces the size of UDP responses for query
type ANY by returning a single arbitrarily selected RRset instead of
all RRsets.
* A new masterfile-style zone 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-method can now be set to date. On update, the serial
number will be set to the current date in YYYYMMDDNN format.
* dnssec-signzone -N date sets 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 +ttlunits prints TTL values with time-unit suffixes: w, d, h, m, s
for weeks, days, hours, minutes, and seconds.
* dig +unknownformat prints dig output in RFC 3597 "unknown record"
presentation format.
* dig +ednsopt allows dig to set arbitrary EDNS options on requests.
* dig +ednsflags allows dig to set yet-to-be-defined EDNS flags on
requests.
* mdig is 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-rate no longer controls NOTIFY messages. These are
separately controlled by notify-rate and startup-notify-rate.
* nsupdate now performs check-names processing by default on records to
be added. This can be disabled with check-names no.
* The statistics channel now supports DEFLATE compression, reducing the
size of the data sent over the network when querying statistics.
* New counters have been added to the statistics channel to track the
sizes of incoming queries and outgoing responses in histogram buckets,
as specified in RSSAC002.
* A new NXDOMAIN redirect method (option nxdomain-redirect) has been
added, allowing redirection to a specified DNS namespace instead of a
single redirect zone.
* When starting up, named now ensures that no other named process is
already running.
* Files created by named to store information, including mkeys and nzf
files, 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
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.
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
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 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, use
specify the prefix using "--with-geoip=/prefix".
For DNSTAP packet logging, you must have libfstrm https://github.com/
farsightsec/fstrm and libprotobuf-c https://developers.google.com/
protocol-buffers, and BIND must be configured with "--enable-dnstap".
Python requires the 'argparse' and 'ply' 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.
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 by running the script 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)