2. BIND Resource Requirements

2.1. Hardware Requirements

DNS hardware requirements have traditionally been quite modest. For many installations, servers that have been retired from active duty have performed admirably as DNS servers.

However, the DNSSEC features of BIND 9 may be quite CPU-intensive, so organizations that make heavy use of these features may wish to consider larger systems for these applications. BIND 9 is fully multithreaded, allowing full utilization of multiprocessor systems for installations that need it.

2.2. CPU Requirements

CPU requirements for BIND 9 range from i386-class machines, for serving static zones without caching, to enterprise-class machines to process many dynamic updates and DNSSEC-signed zones, serving many thousands of queries per second.

2.3. Memory Requirements

Server memory must be sufficient to hold both the cache and the zones loaded from disk. The max-cache-size option can limit the amount of memory used by the cache, at the expense of reducing cache hit rates and causing more DNS traffic. It is still good practice to have enough memory to load all zone and cache data into memory; unfortunately, the best way to determine this for a given installation is to watch the name server in operation. After a few weeks, the server process should reach a relatively stable size where entries are expiring from the cache as fast as they are being inserted.

2.4. Name Server-Intensive Environment Issues

For name server-intensive environments, there are two configurations that may be used. The first is one where clients and any second-level internal name servers query the main name server, which has enough memory to build a large cache; this approach minimizes the bandwidth used by external name lookups. The second alternative is to set up second-level internal name servers to make queries independently. In this configuration, none of the individual machines need to have as much memory or CPU power as in the first alternative, but this has the disadvantage of making many more external queries, as none of the name servers share their cached data.

2.5. Supported Platforms

Current support status of various platforms and BIND 9 versions can be found in the ISC Knowledgebase:

https://kb.isc.org/docs/supported-platforms

In general, this version of BIND will build and run on any POSIX-compliant system with a C11-compliant C compiler, BSD-style sockets with RFC-compliant IPv6 support, POSIX-compliant threads, and the required libraries.

The following C11 features are used in BIND 9:

  • Atomic operations support from the compiler is needed, either in the form of builtin operations, C11 atomics, or the Interlocked family of functions on Windows.

  • Thread Local Storage support from the compiler is needed, either in the form of C11 _Thread_local/thread_local, the __thread GCC extension, or the __declspec(thread) MSVC extension on Windows.

ISC regularly tests BIND on many operating systems and architectures, but lacks the resources to test all of them. Consequently, ISC is only able to offer support on a “best effort” basis for some.

2.5.1. Regularly tested platforms

As of August 2022, BIND 9.16 is fully supported and regularly tested on the following systems:

  • Debian 10, 11

  • Ubuntu LTS 18.04, 20.04, 22.04

  • Fedora 36

  • Red Hat Enterprise Linux / CentOS / Oracle Linux 7, 8

  • FreeBSD 12.3, 13.1

  • OpenBSD 7.1

  • Alpine Linux 3.16

The amd64, i386, armhf and arm64 CPU architectures are all fully supported.

2.5.2. Best effort

The following are platforms on which BIND is known to build and run. ISC makes every effort to fix bugs on these platforms, but may be unable to do so quickly due to lack of hardware, less familiarity on the part of engineering staff, and other constraints. With the exception of Windows Server 2016, none of these are tested regularly by ISC.

  • Windows Server 2012 R2, 2016 / x64

  • Windows 10 / x64

  • macOS 10.12+

  • Solaris 11

  • NetBSD

  • Other Linux distributions still supported by their vendors, such as:

    • Ubuntu 20.10+

    • Gentoo

    • Arch Linux

  • OpenWRT/LEDE 17.01+

  • Other CPU architectures (mips, mipsel, sparc, …)

2.5.3. Community maintained

These systems may not all have the required dependencies for building BIND easily available, although it will be possible in many cases to compile those directly from source. The community and interested parties may wish to help with maintenance, and we welcome patch contributions, although we cannot guarantee that we will accept them. All contributions will be assessed against the risk of adverse effect on officially supported platforms.

  • Platforms past or close to their respective EOL dates, such as:

    • Ubuntu 14.04, 16.04 (Ubuntu ESM releases are not supported)

    • CentOS 6

    • Debian 8 Jessie, 9 Stretch

    • FreeBSD 10.x, 11.x

2.6. Unsupported Platforms

These are platforms on which BIND 9.16 is known not to build or run:

  • Platforms without at least OpenSSL 1.0.2

  • Windows 10 / x86

  • Windows Server 2012 and older

  • Solaris 10 and older

  • Platforms that don’t support IPv6 Advanced Socket API (RFC 3542)

  • Platforms that don’t support atomic operations (via compiler or library)

  • Linux without NPTL (Native POSIX Thread Library)

  • Platforms on which libuv cannot be compiled

2.7. Building BIND 9

To build on a Unix or Linux system, use:

$ ./configure
$ make

Several environment variables affect compilation, and they can be set before running configure. The most significant ones are:

Variable

Description

CC

The C compiler to use. configure tries to figure out the right one for supported systems.

CFLAGS

The C compiler flags. Defaults to include -g and/or -O2 as supported by the compiler. Please include -g if CFLAGS needs to be set.

STD_CINCLUDES

System header file directories. Can be used to specify where add-on thread or IPv6 support is, for example. Defaults to empty string.

STD_CDEFINES

Any additional preprocessor symbols you want defined. Defaults to empty string. For a list of possible settings, see the file OPTIONS.

LDFLAGS

The linker flags. Defaults to an 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

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.

2.7.1. Required Libraries

To build BIND 9, the following packages must be installed:

  • libcrypto, libssl

  • libuv

  • perl

  • pkg-config / pkgconfig / pkgconf

BIND 9.16 requires libuv 1.x or higher. On older systems, an updated libuv package needs to be installed from sources such as EPEL, PPA, or other native sources. The other option is to build and install libuv from source.

OpenSSL 1.0.2e or newer is required. If the OpenSSL library is installed in a nonstandard location, specify the prefix using --with-openssl=<PREFIX> on the configure command line.

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.

2.7.2. Optional Features

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

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

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 zlib (https://zlib.net/). 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 (https://github.com/LMDB/lmdb). If this is installed in a nonstandard location, specify the prefix using --with-lmdb=/prefix.

To support MaxMind GeoIP2 location-based ACLs, the server must be linked with libmaxminddb (https://maxmind.github.io/libmaxminddb/). This is turned on by default if the library is found; if the library is installed in a nonstandard location, specify the prefix using --with-maxminddb=/prefix. GeoIP2 support can be switched off with --disable-geoip.

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

To support internationalized domain names in dig, libidn2 (https://www.gnu.org/software/libidn/#libidn2) must be installed. If the library is installed in a nonstandard location, specify the prefix using --with-libidn2=/prefix or adjust PKG_CONFIG_PATH.

For line editing in nsupdate and nslookup, either the readline (https://tiswww.case.edu/php/chet/readline/rltop.html) or the libedit library (https://www.thrysoee.dk/editline/) must be installed. If these are installed at a nonstandard location, adjust PKG_CONFIG_PATH. readline is used by default, and libedit can be explicitly requested using --with-readline=libedit.

Certain compiled-in constants and default settings can be decreased to values better suited to small machines, e.g. OpenWRT boxes, by specifying --with-tuning=small on the configure command line. This decreases memory usage by using smaller structures, but degrades performance.

On Linux, process capabilities are managed in user space using the libcap library (https://git.kernel.org/pub/scm/libs/libcap/libcap.git/), 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 while processing every query. This option should only be enabled when debugging because is has a significant negative impact on query performance.

make install installs 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.

The option --sysconfdir can be specified to set the directory where configuration files such as named.conf go by default; --localstatedir can be used to set the default parent directory of run/named.pid. --sysconfdir defaults to $prefix/etc and --localstatedir defaults to $prefix/var.

2.7.3. macOS

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