NAMED(8) BIND 9 NAMED(8)
NAME
named - Internet domain name server
SYNOPSIS
named [ [-4] | [-6] ] [-c config-file] [-d debug-level] [-D string] [-E
engine-name] [-f] [-g] [-L logfile] [-M option] [-m flag] [-n #cpus]
[-p port] [-s] [-S #max-socks] [-t directory] [-U #listeners] [-u user]
[-v] [-V] [-X lock-file] [-x cache-file]
DESCRIPTION
named is a Domain Name System (DNS) server, part of the BIND 9 distri-
bution from ISC. For more information on the DNS, see RFC 1033, RFC
1034, and RFC 1035.
When invoked without arguments, named will read the default configura-
tion file /etc/named.conf, read any initial data, and listen for
queries.
OPTIONS
-4 Use IPv4 only even if the host machine is capable of IPv6. -4
and -6 are mutually exclusive.
-6 Use IPv6 only even if the host machine is capable of IPv4. -4
and -6 are mutually exclusive.
-c config-file
Use config-file as the configuration file instead of the de-
fault, /etc/named.conf. To ensure that reloading the configura-
tion file continues to work after the server has changed its
working directory due to to a possible directory option in the
configuration file, config-file should be an absolute pathname.
-d debug-level
Set the daemon's debug level to debug-level. Debugging traces
from named become more verbose as the debug level increases.
-D string
Specifies a string that is used to identify a instance of named
in a process listing. The contents of string are not examined.
-E engine-name
When applicable, specifies the hardware to use for cryptographic
operations, such as a secure key store used for signing.
When BIND is built with OpenSSL PKCS#11 support, this defaults
to the string "pkcs11", which identifies an OpenSSL engine that
can drive a cryptographic accelerator or hardware service mod-
ule. When BIND is built with native PKCS#11 cryptography (--en-
able-native-pkcs11), it defaults to the path of the PKCS#11
provider library specified via "--with-pkcs11".
-f Run the server in the foreground (i.e. do not daemonize).
-g Run the server in the foreground and force all logging to
stderr.
-L logfile
Log to the file logfile by default instead of the system log.
-M option
Sets the default memory context options. If set to external,
this causes the internal memory manager to be bypassed in favor
of system-provided memory allocation functions. If set to fill,
blocks of memory will be filled with tag values when allocated
or freed, to assist debugging of memory problems. (nofill dis-
ables this behavior, and is the default unless named has been
compiled with developer options.)
-m flag
Turn on memory usage debugging flags. Possible flags are usage,
trace, record, size, and mctx. These correspond to the
ISC_MEM_DEBUGXXXX flags described in <isc/mem.h>.
-n #cpus
Create #cpus worker threads to take advantage of multiple CPUs.
If not specified, named will try to determine the number of CPUs
present and create one thread per CPU. If it is unable to deter-
mine the number of CPUs, a single worker thread will be created.
-p port
Listen for queries on port port. If not specified, the default
is port 53.
-s Write memory usage statistics to stdout on exit.
NOTE:
This option is mainly of interest to BIND 9 developers and may be
removed or changed in a future release.
-S #max-socks
Allow named to use up to #max-socks sockets. The default value
is 21000 on systems built with default configuration options,
and 4096 on systems built with "configure --with-tuning=small".
WARNING:
This option should be unnecessary for the vast majority of users.
The use of this option could even be harmful because the specified
value may exceed the limitation of the underlying system API. It is
therefore set only when the default configuration causes exhaustion
of file descriptors and the operational environment is known to sup-
port the specified number of sockets. Note also that the actual max-
imum number is normally a little fewer than the specified value be-
cause named reserves some file descriptors for its internal use.
-t directory
Chroot to directory after processing the command line arguments,
but before reading the configuration file.
WARNING:
This option should be used in conjunction with the -u option, as ch-
rooting a process running as root doesn't enhance security on most
systems; the way chroot(2) is defined allows a process with root
privileges to escape a chroot jail.
-U #listeners
Use #listeners worker threads to listen for incoming UDP packets
on each address. If not specified, named will calculate a de-
fault value based on the number of detected CPUs: 1 for 1 CPU,
and the number of detected CPUs minus one for machines with more
than 1 CPU. This cannot be increased to a value higher than the
number of CPUs. If -n has been set to a higher value than the
number of detected CPUs, then -U may be increased as high as
that value, but no higher. On Windows, the number of UDP listen-
ers is hardwired to 1 and this option has no effect.
-u user
Setuid to user after completing privileged operations, such as
creating sockets that listen on privileged ports.
NOTE:
On Linux, named uses the kernel's capability mechanism to drop all
root privileges except the ability to bind(2) to a privileged port
and set process resource limits. Unfortunately, this means that the
-u option only works when named is run on kernel 2.2.18 or later, or
kernel 2.3.99-pre3 or later, since previous kernels did not allow
privileges to be retained after setuid(2).
-v Report the version number and exit.
-V Report the version number and build options, and exit.
-X lock-file
Acquire a lock on the specified file at runtime; this helps to
prevent duplicate named instances from running simultaneously.
Use of this option overrides the lock-file option in named.conf.
If set to none, the lock file check is disabled.
-x cache-file
Load data from cache-file into the cache of the default view.
WARNING:
This option must not be used. It is only of interest to BIND 9 de-
velopers and may be removed or changed in a future release.
SIGNALS
In routine operation, signals should not be used to control the name-
server; rndc should be used instead.
SIGHUP Force a reload of the server.
SIGINT, SIGTERM
Shut down the server.
The result of sending any other signals to the server is undefined.
CONFIGURATION
The named configuration file is too complex to describe in detail here.
A complete description is provided in the BIND 9 Administrator Refer-
ence Manual.
named inherits the umask (file creation mode mask) from the parent
process. If files created by named, such as journal files, need to have
custom permissions, the umask should be set explicitly in the script
used to start the named process.
FILES
/etc/named.conf
The default configuration file.
/var/run/named/named.pid
The default process-id file.
SEE ALSO
RFC 1033, RFC 1034, RFC 1035, named-checkconf(8), named-checkzone(8),
rndc(8), :manpage:`named.conf(5), BIND 9 Administrator Reference Man-
ual.
AUTHOR
Internet Systems Consortium
COPYRIGHT
2020, Internet Systems Consortium
9.16.8-Debian 2020-10-13 NAMED(8)