Provided by: bind9_9.16.48-0ubuntu0.20.04.1_amd64 bug


       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] [-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 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 pathname.

          This option prints out the default built-in configuration and exits.

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

       -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 signing.

              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).  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     This option runs the server in the foreground (i.e., do not daemonize).

       -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:

          • external:  use  system-provided  memory  allocation  functions;  this is the implicit

          • internal: use the internal memory manager.

          • 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 --enable-developer.

          • nofill: disable the behavior enabled by fill; this is  the  implicit  default  unless
            named has been compiled with --enable-developer.

       -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 controls the number of CPUs that named assumes the presence of. If not
              specified, named tries to determine the number of CPUs present automatically; if it
              fails, a single CPU is assumed to be present.

              named  creates  two  threads  per  each  CPU  present (one thread for receiving and
              sending client traffic and  another  thread  for  sending  and  receiving  resolver
              traffic) and then on top of that a single thread for handling time-based events.

       -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 configuration options, and 4096 on systems
              built with configure --with-tuning=small.

          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 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  is  defined
          allows a process with root privileges 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 ports.

          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 disabled.

       -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 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