|`CC`|The C compiler to use. `configure` tries to figure out the right one for supported systems.|
|`CFLAGS`|C compiler flags. Defaults to include -g and/or -O2 as supported by the compiler. Please include '-g' if you need to set `CFLAGS`. |
|`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](OPTIONS.md).|
|`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`||
#### <a name="opts"/> 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](http://xmlsoft.org) or json-c
[https://github.com/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
| [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 |
| [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.
### <a name="ack"/> 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
