named(8)
NAMED(8) BIND9 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] [-M option]
[-m flag] [-n #cpus] [-p port] [-s] [-S #max-socks]
[-t directory] [-U #listeners] [-u user] [-v] [-V]
[-x cache-file]
DESCRIPTION
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 will read the default
configuration 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
default, /etc/named.conf. To 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 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
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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".
-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.
-M option
Sets the default memory context options. Currently the
only supported option is external, which causes the
internal memory manager to be bypassed in favor of
system-provided memory allocation functions.
-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 determine 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.
9
-S #max-socks
Allow named to use up to #max-socks sockets. The default
value is 4096 on systems built with default
configuration options, and 21000 on systems built with
"configure --with-tuning=large".
Warning
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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.
9
-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 chrooting 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.
9
-U #listeners
Use #listeners 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. 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 listeners 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).
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-v
Report the version number and exit.
-V
Report the version number and build options, and exit.
-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 developers and may be removed or changed
in a future release.
9
SIGNALS
In routine operation, signals should not be used to control
the nameserver; 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 Reference 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), lwresd(8), named.conf(5), BIND 9
Administrator Reference Manual.
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AUTHOR
Internet Systems Consortium, Inc.
COPYRIGHT
Copyright 8c9 2004-2009, 2011, 2013-2016 Internet Systems
Consortium, Inc. ("ISC")
Copyright 8c9 2000, 2001, 2003 Internet Software Consortium.
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