named — Internet domain name server
-c ] [
-d ] [
-D ] [
-E ] [
-L ] [
-M ] [
-m ] [
-n ] [
-p ] [
-S ] [
-t ] [
-U ] [
-u ] [
-X ] [
named is a Domain Name System (DNS) server, part of the BIND 9 distribution from ISC. For more information on the DNS, see RFCs 1033, 1034, and 1035.
When invoked without arguments, named
read the default configuration file
/etc/named.conf, read any initial
data, and listen for queries.
Use IPv4 only even if the host machine is capable of IPv6.
-6 are mutually
Use IPv6 only even if the host machine is capable of IPv4.
-6 are mutually
config-file as the
configuration file instead of the default,
ensure that reloading the configuration file continues
to work after the server has changed its working
directory due to to a possible
directory option in the configuration
config-file should be
an absolute pathname.
Set the daemon's debug level to
Debugging traces from named become
more verbose as the debug level increases.
Specifies a string that is used to identify a instance of
named in a process listing. The contents
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 module. When BIND is built with native PKCS#11 cryptography (--enable-native-pkcs11), it defaults to the path of the PKCS#11 provider library specified via "--with-pkcs11".
Run the server in the foreground (i.e. do not daemonize).
Run the server in the foreground and force all logging
Log to the file
logfile by default
instead of the system log.
Sets the default memory context options. Currently
the only supported option is
which causes the internal memory manager to be bypassed
in favor of system-provided memory allocation functions.
Turn on memory usage debugging flags. Possible flags are
These correspond to the ISC_MEM_DEBUGXXXX flags described in
#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 determine the number of CPUs, a
single worker thread will be created.
Listen for queries on port
port. If not
specified, the default is port 53.
Write memory usage statistics to
stdout on exit.
This option is mainly of interest to BIND 9 developers and may be removed or changed in a future release.
Allow named to use up to
The default value is 4096 on systems built with default
configuration options, and 21000 on systems built with
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 support the specified number of sockets. Note also that the actual maximum number is normally a little fewer than the specified value because named reserves some file descriptors for its internal use.
processing the command line arguments, but before
reading the configuration file.
This option should be used in conjunction with the
-u option, as chrooting a process
running as root doesn't enhance security on most
systems; the way
defined allows a process with root privileges to
escape a chroot jail.
worker threads to listen for incoming UDP packets on each
address. If not specified, named will
calculate a default 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.
-n has been set to a higher value than
the number of detected CPUs, then
be increased as high as that value, but no higher.
On Windows, the number of UDP listeners is hardwired to 1
and this option has no effect.
user after completing
privileged operations, such as creating sockets that
listen on privileged ports.
On Linux, named uses the kernel's
capability mechanism to drop all root privileges
except the ability to
privileged port and set process resource limits.
Unfortunately, this means that the
option only works when named is
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
Report the version number and exit.
Report the version number and build options, and exit.
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
If set to
none, the lock file check
Load data from
cache-file into the
cache of the default view.
This option must not be used. It is only of interest to BIND 9 developers and may be removed or changed in a future release.
In routine operation, signals should not be used to control the nameserver; rndc should be used instead.
Force a reload of the server.
Shut down the server.
The result of sending any other signals to the server is undefined.
The named configuration file is too complex to describe in detail here. A complete description is provided in the BIND 9 Administrator Reference Manual.
named inherits the
(file creation mode mask) from the parent process. If files
created by named, such as journal files,
need to have custom permissions, the
should be set explicitly in the script used to start the
The default configuration file.
The default process-id file.