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named(8)                            BIND 9                            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  distri-
       bution  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  /etc/named.conf, reads any initial data, and listens for queries.


       -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, /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  path-

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

       -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 acceler-
              ator  or  hardware service module (usually pkcs11). When BIND is
              built with native PKCS#11 cryptography (--enable-native-pkcs11),
              it  defaults  to the path of the PKCS#11 provider library speci-
              fied via --with-pkcs11.

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

       -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 memory context options. If set to
              external, the internal memory manager is bypassed  in  favor  of
              system-provided  memory  allocation  functions.  If set to fill,
              blocks of memory are filled with tag values  when  allocated  or
              freed,  to  assist debugging of memory problems. nofill disables
              this behavior, and is the default unless named has been compiled
              with developer options.

       -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 port
              This  option  listens for queries on port. If not specified, the
              default is port 53.

       -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  allows  named to use up to #max-socks sockets. The
              default value is 21000 on systems built with default  configura-
              tion   options,   and  4096  on  systems  built  with  configure

          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 sup-
          port the specified number of sockets. Note also that the actual max-
          imum 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 privi-
          leges to escape a chroot jail.

       -U #listeners
              This option tells named the number of #listeners worker  threads
              to  listen  on, for incoming UDP packets on each address. If not
              specified, named calculates 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
              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 and  build  options,  and

       -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

       -x cache-file
              This  option  loads  data  from cache-file into the cache of the
              default view.

          This option must not be used in normal operations.  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  name-
       server; 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  Refer-
       ence 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


       2021, Internet Systems Consortium

9.16.12                           2021-02-04                          named(8)

bind 9.16.12 - Generated Sat Feb 20 15:02:46 CST 2021
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