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man pages section 8: System Administration Commands

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Updated: Wednesday, February 9, 2022

named (8)


named - Internet domain name server


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]


NAMED(8)                             BIND9                            NAMED(8)

       named - Internet domain name server

       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]

       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.

           Use IPv4 only even if the host machine is capable of IPv6.  -4 and
           -6 are mutually exclusive.

           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".

           Run the server in the foreground (i.e. do not daemonize).

           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. 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.

           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.

       -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".

               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.

               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, 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.

               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

           Report the version number and exit.

           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.

               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 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.

           The default configuration file.

           The default process-id file.

       See attributes(7) for descriptions of the following attributes:

       |Availability   | network/dns/bind         |
       |Stability      | Pass-through uncommitted |

       RFC 1033, RFC 1034, RFC 1035, named-checkconf(8), named-checkzone(8),
       rndc(8), dns-server(8s), named.conf(5), BIND 9 Administrator Reference

       The BIND 9 Administrator's Reference Manual is available online or, if
       locally installed, at file:///usr/share/doc/bind/html/Bv9ARM.html and

       Some compile-time features documented in the ARM are not available; to
       see a list of enabled features run '/usr/sbin/named -V'.

       Internet Systems Consortium, Inc.

       Copyright (C) 2000, 2001, 2003-2009, 2011, 2013-2021 Internet Systems
       Consortium, Inc. ("ISC")

       Source code for open source software components in Oracle Solaris can
       be found at https://www.oracle.com/downloads/opensource/solaris-source-

       This software was built from source available at
       https://github.com/oracle/solaris-userland.  The original community
       source was downloaded from

       Further information about this software can be found on the open source
       community website at http://www.isc.org/software/bind/.

ISC                               2014-02-19                          NAMED(8)