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 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.
-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: 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.
-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.
-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, 2 for 2-4
CPUs, and the number of detected CPUs divided by 2 for values
higher than 4. 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.
-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 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.
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.
AUTHOR
Internet Systems Consortium
COPYRIGHT
Copyright 2004-2009, 2011, 2013-2015 Internet Systems Consortium,
Inc. ("ISC")
Copyright 2000, 2001, 2003 Internet Software Consortium.
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