Name
named — Internet domain name server
Synopsis
named [-4] [-6] [-c config-file] [-d debug-level] [-E engine-name] [-f] [-g] [-m flag] [-n #cpus] [-p port] [-s] [-S #max-socks] [-t directory] [-u user] [-v] [-V] [-x cache-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 RFCs 1033, 1034, and 1035.
When invoked without arguments, named
will
read the default configuration file
/etc/named.conf, read any initial
data, and listen for queries.
OPTIONS
- -4
Use IPv4 only even if the host machine is capable of IPv6.
-4 and -6 are mutually
exclusive.
- -6
Use IPv6 only even if the host machine is capable of IPv4.
-4 and -6 are mutually
exclusive.
- -c
config-file
Use config-file as the
configuration file instead of the default,
/etc/named.conf. To
ensure that reloading the configuration file continues
to work 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.
- -d
debug-level
Set the daemon's debug level to debug-level.
Debugging traces from named become
more verbose as the debug level increases.
- -E
engine-name
Use a crypto hardware (OpenSSL engine) for the crypto operations
it supports, for instance re-signing with private keys from
a secure key store. When compiled with PKCS#11 support
engine-name
defaults to pkcs11, the empty name resets it to no engine.
- -f
Run the server in the foreground (i.e. do not daemonize).
- -g
Run the server in the foreground and force all logging
to stderr.
- -m
flag
Turn 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
Create #cpus worker threads
to take advantage of multiple CPUs. If not specified,
named will try to determine the
number of CPUs present and create one thread per CPU.
If it is unable to determine the number of CPUs, a
single worker thread will be created.
- -p
port
Listen for queries on port port. If not
specified, the default is port 53.
- -s
-
Write 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
-
Allow named to use up to
#max-socks sockets.
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 a little
fewer than the specified value because
named reserves some file descriptors
for its internal use.
- -t
directory
-
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(2) is
defined allows a process with root privileges to
escape a chroot jail.
- -u
user
-
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(2) 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(2).
- -v
Report the version number and exit.
- -V
Report the version number and build options, and exit.
- -x
cache-file
-
Load data from cache-file into the
cache of the default view.
Warning
This option must not be used. It is only of interest
to BIND 9 developers and may be removed or changed in a
future release.
SIGNALS
In routine operation, signals should not be used to control
the nameserver; rndc should be used
instead.
- SIGHUP
Force a reload of the server.
- SIGINT, SIGTERM
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/named.conf
The default configuration file.
/var/run/named/named.pid
The default process-id file.
SEE ALSO
RFC 1033,
RFC 1034,
RFC 1035,
named-checkconf(8),
named-checkzone(8),
rndc(8),
lwresd(8),
named.conf(5),
BIND 9 Administrator Reference Manual.
AUTHOR
Internet Systems Consortium
