Ubuntu Manpage: named - Internet domain name server

Provided by: bind9_9.18.28-0ubuntu0.20.04.1_amd64

NAME

       named - Internet domain name server

SYNOPSIS

       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]

DESCRIPTION

       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/bind/named.conf, reads any initial data, and listens for queries.

OPTIONS

-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/bind/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 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).

-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:

• 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 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.

NOTE:
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.

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 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.

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 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).

WARNING:
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 ports.

NOTE:
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.

SIGNALS

       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.

       SIGINT, SIGTERM
              These signals 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/bind/named.conf
              The default configuration file.

       /run/named.pid
              The default process-id file.

AUTHOR

       Internet Systems Consortium

COPYRIGHT

       2024, Internet Systems Consortium