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named(8)                            BIND 9                            named(8)


       named - Internet domain name server


       named [ [-4] | [-6] ] [-c config-file] [-C] [-d debug-level] [-D
       string] [-E engine-name] [-f] [-g] [-L logfile] [-M option] [-m flag]
       [-n #cpus] [-p port] [-s] [-t directory] [-U #listeners] [-u user] [-v]
       [-V] [-X lock-file]


       named is a Domain Name System (DNS) server, part of the BIND 9
       distribution from ISC. For more information on the DNS, see RFC 1033,
       RFC 1034, and RFC 1035.

       When invoked without arguments, named reads the default configuration
       file /opt/local/etc/named.conf, reads any initial data, and listens for


       -4     This option tells named to use only IPv4, even if the host
              machine is capable of IPv6. -4 and -6 are mutually exclusive.

       -6     This option tells named to use only IPv6, even if the host
              machine is capable of IPv4. -4 and -6 are mutually exclusive.

       -c config-file
              This option tells named to use config-file as its configuration
              file instead of the default, /opt/local/etc/named.conf. To
              ensure that the configuration file can be reloaded 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.

       -C     This option prints out the default built-in configuration and

              NOTE: This is for debugging purposes only and is not an accurate
              representation of the actual configuration used by named at

       -d debug-level
              This option sets the daemon's debug level to debug-level.
              Debugging traces from named become more verbose as the debug
              level increases.

       -D string
              This option 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, this option specifies the hardware to use for
              cryptographic operations, such as a secure key store used for

              When BIND 9 is built with OpenSSL, this needs to be set to the
              OpenSSL engine identifier that drives the cryptographic
              accelerator or hardware service module (usually pkcs11).

       -f     This option runs the server in the foreground (i.e., do not

       -g     This option runs the server in the foreground and forces all
              logging to stderr.

       -L logfile
              This option sets the log to the file logfile by default, instead
              of the system log.

       -M option
              This option sets the default (comma-separated) memory context
              options. The possible flags are:

              o fill: fill blocks of memory with tag values when they are
                allocated or freed, to assist debugging of memory problems;
                this is the implicit default if named has been compiled with

              o nofill: disable the behavior enabled by fill; this is the
                implicit default unless named has been compiled with

       -m flag
              This option turns 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
              This option creates #cpus worker threads to take advantage of
              multiple CPUs. If not specified, named tries to determine the
              number of CPUs present and creates one thread per CPU. If it is
              unable to determine the number of CPUs, a single worker thread
              is created.

       -p value
              This option specifies the port(s) on which the server will
              listen for queries. If value is of the form <portnum> or
              dns=<portnum>, the server will listen for DNS queries on
              portnum; if not not specified, the default is port 53. If value
              is of the form tls=<portnum>, the server will listen for TLS
              queries on portnum; the default is 853.  If value is of the form
              https=<portnum>, the server will listen for HTTPS queries on
              portnum; the default is 443.  If value is of the form
              http=<portnum>, the server will listen for HTTP queries on
              portnum; the default is 80.

       -s     This option writes 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
              This option is deprecated and no longer has any function.

          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 slightly fewer than the specified value,
          because named reserves some file descriptors for its internal use.

       -t directory
              This option tells named to chroot to directory after processing
              the command-line arguments, but before reading the configuration

          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 is defined allows a process with root
          privileges to escape a chroot jail.

       -U #dispatches
              This option specifies the number of per-interface UDP
              #dispatches that named should use to handle the outgoing
              (recursive) UDP connection, to reduce contention between the
              resolver threads.

              If not specified, named calculates a default value based on the
              number of detected CPUs: 1 for a single 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 (see -n on how to override the value).

          This option should be unnecessary for the vast majority of users,
          and will be removed in the next version of BIND 9.

       -u user
              This option sets the setuid to user after completing privileged
              operations, such as creating sockets that listen on privileged

          On Linux, named uses the kernel's capability mechanism to drop all
          root privileges except the ability to bind 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.

       -v     This option reports the version number and exits.

       -V     This option reports the version number, build options, supported
              cryptographics algorithms, and exits.

       -X lock-file
              This option acquires 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


       In routine operation, signals should not be used to control the
       nameserver; rndc should be used instead.

       SIGHUP This signal forces a reload of the server.

              These signals 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.


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


       Internet Systems Consortium


       2024, Internet Systems Consortium

9.18.27                           2024-05-03                          named(8)

bind 9.18.27 - Generated Thu May 16 16:29:06 CDT 2024
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