named(8) BSD System Manager's Manual
named(8)
NAME
named - Internet domain name server (DNS)
SYNOPSIS
named [-d debuglevel] [-p port#] [-(b|c) config_file] [-f -q
-r -v] [-u
user_name] [-g group_name] [-t directory] [-w
directory]
[config_file]
DESCRIPTION
Named is the Internet domain name server. See RFC's 1033,
1034, and 1035
for more information on the Internet name-domain system.
Without any ar-
guments, named will read the default configuration file
/etc/named.conf,
read any initial data, and listen for queries. A
config_file argument
given at the end of the command line will override any
config_file speci-
fied by using the ``-b'' or ``-c'' flags.
NOTE: Several of named's options, and much more of its be-
haviour, can be
controlled in the configuration file. Please refer to the
configuration
file guide included with this BIND distribution for further
information.
Options are:
-d debuglevel
Print debugging information. The debuglevel is
a number de-
termines the level of messages printed. If neg-
ative,
debuglevel is set to ``1''.
NOTE: The new debugging framework is consider-
ably more so-
phisticated than it was in older versions of
named. The con-
figuration file's ``logging'' statement allows
for multiple,
distinct levels of debugging for each of a large
set of cate-
gories of events (such as queries, transfers in
or out,
etc.). Please refer to the configuration file
guide included
with this BIND distribution for further informa-
tion about
these extensive new capabilities.
-p port# Use the specified remote port number; this is
the port number
to which named will send queries. The default
value is the
standard port number, i.e., the port number re-
turned by get-
servbyname(3) for service ``domain''.
NOTE: Previously, the syntax ``-p
port#[/localport#]'' was
supported; the first port was that used when
contacting
remote servers, and the second one was the ser-
vice port bound
by the local instance of named. The current us-
age is equiva-
lent to the old usage without the localport#
specified; this
functionality can be specified with the ``lis-
ten-on'' clause
of the configuration file's ``options'' state-
ment.
-(b|c) config_file
Use an alternate config_file; this argument is
overridden by
any config_file which is specified at the end of
the command
line. The default value is /etc/named.conf.
-f Run this process in the foreground; don't
fork(2) and daemo-
nize. (The default is to daemonize.)
-q Trace all incoming queries if named has been
compiled with
QRYLOG defined.
NOTE: This option is deprecated in favor of the
``queries''
logging category of the configuration file's
``logging''
statement; for more information, please refer to
the configu-
ration file guide included with this distribu-
tion of BIND.
-r Turns recursion off in the server. Answers can
come only
from local (primary or secondary) zones. This
can be used on
root servers. The default is to use recursion.
NOTE: This option can be overridden by and is
deprecated in
favor of the ``recursion'' clause of the config-
uration file's
``options'' statement.
-v Report the version and exit.
-u user_name
Specifies the user the server should run as af-
ter it initial-
izes. The value specified may be either a user-
name or a nu-
meric user id. If the ``-g'' flag is not speci-
fied, then the
group id used will be the primary group of the
user specified
(initgroups() is called, so all of the user's
groups will be
available to the server).
-g group_name
Specifies the group the server should run as af-
ter it ini-
tializes. The value specified may be either a
groupname or a
numeric group id.
-t directory
Specifies the directory the server should ch-
root() into as
soon as it is finshed processing command line
arguments.
-w directory
Sets the working directory of the server. The
``directory''
clause of the configuration file's ``options''
statement
overrides any value specified on the command
line. The de-
fault working directory is the current directory
(``.'').
Any additional argument is taken as the name of the configu-
ration file,
for compatibility with older implementations; as noted
above, this argu-
ment overrides any config_file specified by the use of the
``-b'' or
``-c'' flags. If no further argument is given, then the de-
fault configu-
ration file is used (/etc/named.conf).
Master File Format
The master file consists of control information and a list
of resource
records for objects in the zone of the forms:
$INCLUDE <filename> <opt_domain>
$ORIGIN <domain>
$TTL <ttl>
<domain> <opt_ttl> <opt_class> <type> <re-
source_record_data>
where:
domain is ``.'' for root, ``@'' for the current ori-
gin, or a stan-
dard domain name. If domain is a standard do-
main name that
does not end with ``.'', the current origin is
appended to
the domain. Domain names ending with ``.'' are
unmodified.
opt_domain This field is used to define an origin for the
data in an
included file. It is equivalent to placing an
$ORIGIN
statement before the first line of the includ-
ed file. The
field is optional. Neither the opt_domain
field nor
$ORIGIN statements in the included file modify
the current
origin for this file.
ttl A integer number that sets the default time-
to-live for fu-
ture records without an explicit ttl.
opt_ttl An optional integer number for the time-to-
live field. If
not set the ttl is taken from the last $TTL
statement. If
no $TTL statement has occurred then the SOA
minimum value
is used and a warning is generated.
opt_class The object address type; currently only one
type is sup-
ported, IN, for objects connected to the DARPA
Internet.
type This field contains one of the following to-
kens; the data
expected in the resource_record_data field is
in parenthe-
ses:
A a host address (dotted-quad
IP address)
NS an authoritative name server
(domain)
MX a mail exchanger (domain),
preceded by a
preference value (0..32767),
with lower
numeric values representing
higher logical
preferences.
CNAME the canonical name for an
alias (domain)
SOA marks the start of a zone of
authority
(domain of originating host,
domain ad-
dress of maintainer, a serial
number and
the following parameters in
seconds: re-
fresh, retry, expire and min-
imum TTL (see
RFC 883 and RFC 2308)).
NULL a null resource record (no
format or data)
RP a Responsible Person for some
domain name
(mailbox, TXT-referral)
PTR a domain name pointer (do-
main)
HINFO host information (cpu_type
OS_type)
Resource records normally end at the end of a line, but may
be continued
across lines between opening and closing parentheses. Com-
ments are in-
troduced by semicolons and continue to the end of the line.
NOTE: There are other resource record types not shown here.
You should
consult the BIND Operations Guide (``BOG'') for the complete
list. Some
resource record types may have been standardized in newer
RFC's but not
yet implemented in this version of BIND.
SOA Record Format
Each master zone file should begin with an SOA record for
the zone. An
example SOA record is as follows:
@ IN SOA ucbvax.Berkeley.EDU. rwh.ucb-
vax.Berkeley.EDU. (
1989020501 ; serial
10800 ; refresh
3600 ; retry
3600000 ; expire
86400 ) ; minimum
The SOA specifies a serial number, which should be incre-
mented each time
the master file is changed. Note that the serial number can
be given as
a dotted number, but this is a very unwise thing to do since
the transla-
tion to normal integers is via concatenation rather than
multiplication
and addition. You can spell out the year, month, day of
month, and 0..99
version number and still fit inside the unsigned 32-bit size
of this
field. (It's true that we will have to rethink this strate-
gy in the year
4294, but we're not worried about it.)
Secondary servers check the serial number at intervals spec-
ified by the
refresh time in seconds; if the serial number changes, a
zone transfer
will be done to load the new data. If a master server can-
not be contact-
ed when a refresh is due, the retry time specifies the in-
terval at which
refreshes should be attempted. If a master server cannot be
contacted
within the interval given by the expire time, all data from
the zone is
discarded by secondary servers. The minimum value is the
cache time-to-
live for negative answers (RFC 2308).
NOTES
The boot file directives ``domain'' and ``suffixes'' have
been obsoleted
by a more useful, resolver-based implementation of suffixing
for partial-
ly-qualified domain names. The prior mechanisms could fail
under a num-
ber of situations, especially when then local nameserver did
not have
complete information.
The following signals have the specified effect when sent to
the server
process using the kill(1) command:
SIGHUP Causes server to read named.conf and reload the
database. If
the server is built with the FORCED_RELOAD com-
pile-time option,
then SIGHUP will also cause the server to check
the serial num-
ber on all secondary zones; normally, the serial
numbers are
only checked at the SOA-specified intervals.
SIGINT Dumps the current data base and cache to
``/var/tmp/named_dump.db'' or the value of
_PATH_DUMPFILE.
SIGILL Dumps statistics data into named.stats if the
server is com-
piled with -DSTATS. Statistics data is appended to
the file.
SIGSYS Dumps the profiling data in /var/tmp if the server
is compiled
with profiling (server forks, chdirs and exits).
SIGTERM Saves any modified dynamic zones to the file sys-
tem, and shuts
down the server.
SIGUSR1 Turns on debugging; each SIGUSR1 increments debug
level.
(SIGEMT on older systems without SIGUSR1.)
SIGUSR2 Turns off debugging completely. (SIGFPE on older
systems
without SIGUSR2.)
SIGWINCH Toggles logging of all incoming queries via sys-
log(3) (requires
server to have been built with the QRYLOG option).
FILES
/etc/named.conf default name
server configu-
ration file
/var/run/named.pid (_PATH_PIDFILE) the process id
/var/tmp/named_dump.db (_PATH_DUMPFILE) dump of the name
server
database
/var/tmp/named.run (file: _PATH_DEBUG) debug output
/var/tmp/named.stats (file: _PATH_STATS) nameserver
statistics data
SEE ALSO
named.conf(5), gethostbyname(3), hostname(7), kill(1),
resolver(3),
resolver(5), signal(3), RFC 882, RFC 883, RFC 973, RFC
974, RFC 1033,
RFC 1034, RFC 1035, RFC 1123, RFC 2308 ``Name Server Opera-
tions Guide for
BIND''
4th Berkeley Distribution February 1, 1996
4