NAMED(8) BSD System Manager's Manual NAMED(8)
NAME
named - Internet domain name server
SYNOPSIS
named [-d debuglevel] [-p port#] [[-b]bootfile]
DESCRIPTION
Named is the Internet domain name server. See RFC883 for more informa-
tion on the Internet name-domain system. Without any arguments, named
will read the default boot file /etc/named.boot, read any initial data
and listen for queries.
Options are:
-d Print debugging information. A number after the -d determines
the level of messages printed.
-p Use a different port number. The default is the standard port
number as listed in /etc/services.
-b Use an alternate boot file. This is optional and allows you to
specify a file with a leading dash.
Any additional argument is taken as the name of the boot file. The boot
file contains information about where the name server is to get its ini-
tial data. If multiple boot files are specified, only the last is used.
Lines in the boot file cannot be continued on subsequent lines. The fol-
lowing is a small example:
;
; boot file for name server
;
directory /etc/namedb
; type domain source host/file backup file
cache . root.cache
primary Berkeley.EDU berkeley.edu.zone
primary 32.128.IN-ADDR.ARPA ucbhosts.rev
secondary CC.Berkeley.EDU 128.32.137.8 128.32.137.3 cc.zone.bak
secondary 6.32.128.IN-ADDR.ARPA 128.32.137.8 128.32.137.3 cc.rev.bak
primary 0.0.127.IN-ADDR.ARPA localhost.rev
forwarders 10.0.0.78 10.2.0.78
; slave
The ``directory'' line causes the server to change its working directory
to the directory specified. This can be important for the correct pro-
cessing of $INCLUDE files in primary zone files.
The ``cache'' line specifies that data in ``root.cache'' is to be placed
in the backup cache. Its main use is to specify data such as locations
of root domain servers. This cache is not used during normal operation,
but is used as ``hints'' to find the current root servers. The file
``root.cache'' is in the same format as ``berkeley.edu.zone''. There can
be more than one ``cache'' file specified. The cache files are processed
in such a way as to preserve the time-to-live's of data dumped out. Data
for the root nameservers is kept artificially valid if necessary.
The first ``primary'' line states that the file ``berkeley.edu.zone''
contains authoritative data for the ``Berkeley.EDU'' zone. The file
``berkeley.edu.zone'' contains data in the master file format described
in RFC883. All domain names are relative to the origin, in this case,
``Berkeley.EDU'' (see below for a more detailed description). The second
``primary'' line states that the file ``ucbhosts.rev'' contains authori-
tative data for the domain ``32.128.IN-ADDR.ARPA'', which is used to
translate addresses in network 128.32 to hostnames. Each master file
should begin with an SOA record for the zone (see below).
The first ``secondary'' line specifies that all authoritative data under
``CC.Berkeley.EDU'' is to be transferred from the name server at
128.32.137.8. If the transfer fails it will try 128.32.137.3 and contin-
ue trying the addresses, up to 10, listed on this line. The secondary
copy is also authoritative for the specified domain. The first non-
dotted-quad address on this line will be taken as a filename in which to
backup the transfered zone. The name server will load the zone from this
backup file if it exists when it boots, providing a complete copy even if
the master servers are unreachable. Whenever a new copy of the domain is
received by automatic zone transfer from one of the master servers, this
file will be updated. The second ``secondary'' line states that the ad-
dress-to-hostname mapping for the subnet 128.32.136 should be obtained
from the same list of master servers as the previous zone.
The ``forwarders'' line specifies the addresses of sitewide servers that
will accept recursive queries from other servers. If the boot file spec-
ifies one or more forwarders, then the server will send all queries for
data not in the cache to the forwarders first. Each forwarder will be
asked in turn until an answer is returned or the list is exhausted. If
no answer is forthcoming from a forwarder, the server will continue as it
would have without the forwarders line unless it is in ``slave'' mode.
The forwarding facility is useful to cause a large sitewide cache to be
generated on a master, and to reduce traffic over links to outside
servers. It can also be used to allow servers to run that do not have
access directly to the Internet, but wish to act as though they do.
The ``slave'' line (shown commented out) is used to put the server in
slave mode. In this mode, the server will only make queries to for-
warders. This option is normally used on machine that wish to run a
server but for physical or administrative reasons cannot be given access
to the Internet, but have access to a host that does have access.
The ``sortlist'' line can be used to indicate networks that are to be
preferred over other, unlisted networks. Queries for host addresses from
hosts on the same network as the server will receive responses with local
network addresses listed first, then addresses on the sort list, then
other addresses. This line is only acted on at initial startup. When
reloading the nameserver with a SIGHUP, this line will be ignored.
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>
<domain> <opt_ttl> <opt_class> <type> <resource_record_data>
where domain is `.' for root, `@' for the current origin, or a standard
domain name. If domain is a standard domain name that does not end with
`.', the current origin is appended to the domain. Domain names ending
with `.' are unmodified. The optdomain field is used to define an ori-
gin for the data in an included file. It is equivalent to placing a
$ORIGIN statement before the first line of the included file. The field
is optional. Neither the optdomain field nor $ORIGIN statements in the
included file modify the current origin for this file. The optttl field
is an optional integer number for the time-to-live field. It defaults to
zero, meaning the minimum value specified in the SOA record for the zone.
The optclass field is the object address type; currently only one type
is supported, IN, for objects connected to the DARPA Internet. The type
field contains one of the following tokens; the data expected in the
resourcerecorddata field is in parentheses.
A a host address (dotted quad)
NS an authoritative name server (domain)
MX a mail exchanger (domain)
CNAME the canonical name for an alias (domain)
SOA marks the start of a zone of authority (domain of originating
host, domain address of maintainer, a serial number and the
following parameters in seconds: refresh, retry, expire and
minimum TTL (see RFC883))
MB a mailbox domain name (domain)
MG a mail group member (domain)
MR a mail rename domain name (domain)
NULL ra null resource record (no format or data)
WKS a well know service description (not implemented yet)
PTR a domain name pointer (domain)
HINFO host information (cpu_type OS_type )
MINFO mailbox or mail list information (request_domain er-
ror_domain)
Resource records normally end at the end of a line, but may be continued
across lines between opening and closing parentheses. Comments are in-
troduced by semicolons and continue to the end of the line.
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.ucbvax.Berkeley.EDU. (
2.89 ; serial
10800 ; refresh
3600 ; retry
3600000 ; expire
86400 ) ; minimum
The SOA lists a serial number, which should be changed each time the mas-
ter file is changed. Secondary servers check the serial number at inter-
vals specified 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 cannot be contacted when a refresh is due, the retry time speci-
fies the interval at which refreshes should be attempted until success-
ful. 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 time-to-live used by records in the
file with no explicit time-to-live value.
NOTES
The boot file directives ``domain'' and ``suffixes'' have been obsoleted
by a more useful resolver based implementation of suffixing for partially
qualified domain names. The prior mechanisms could fail under a number
of situations, especially when then local nameserver did not have com-
plete 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.boot and reload database.
SIGINT Dumps current data base and cache to /var/tmp/nameddump.db
SIGIOT Dumps statistics data into /var/tmp/named.stats if the server
is compiled -DSTATS. Statistics data is appended to the file.
SIGSYS Dumps the profiling data in /var/tmp if the server is com-
piled with profiling (server forks, chdirs and exits).
SIGTERM Dumps the primary and secondary database files. Used to save
modified data on shutdown if the server is compiled with dy-
namic updating enabled.
SIGUSR1 urnsTurns on debugging; each SIGUSR1 increments debug level.
(SIGEMT on older systems without SIGUSR1)
SIGUSR2 Turns off debugging completely. (SIGFPE on older systems
without SIGUSR2)
FILES
/etc/named.boot name server configuration boot file
/etc/named.pid the process id
/var/tmp/named.run debug output
/var/tmp/named_dump.db dump of the name server database
/var/tmp/named.stats nameserver statistics data
SEE ALSO
kill(1), gethostbyname(3), signal(3), resolver(3), resolver(5),
hostname(7),
RFC882.
RFC883.
RFC973.
RFC974.
Name Server Operations Guide for BIND.
HISTORY
The named command appeared in 4.3BSD.
4th Berkeley Distribution March 27, 1993 4