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 user] [-v] [-V] ]
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.
- -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).
- -F
- This options turns on FIPS (US Federal Information Processing Standards)
mode if the underlying crytographic library supports running in FIPS
mode.
- -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.
- -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 #listeners
- This option has been removed. Attempts to use it now result in a
warning.
- -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 has been removed and using it will cause a fatal error.
In routine operation, signals should not be used to control the
nameserver; rndc should be used instead.
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.
- /etc/bind/named.conf
- The default configuration file.
- /run/named.pid
- 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