named(8) BIND 9 named(8)
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 /opt/local/etc/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, /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
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:
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
--enable-developer.
o 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
/opt/local/etc/named.conf
The default configuration file.
/opt/local/var/run/named.pid
The default process-id file.
SEE ALSO
RFC 1033, RFC 1034, RFC 1035, named-checkconf(8), named-checkzone(8),
rndc(8), named.conf(5), BIND 9 Administrator Reference Manual.
AUTHOR
Internet Systems Consortium
COPYRIGHT
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