path: root/usr.sbin/named/named.8

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.\"	@(#)named.8	6.6 (Berkeley) 2/14/89
.\"
.TH NAMED 8 "June 20, 1995"
.UC 4
.SH NAME
named \- Internet domain name server
.SH SYNOPSIS
.B named
[
.B \-d
.I debuglevel
] [
.B \-p
.IR port# [\fB/\fP\fIlocalport#\fP]
] [{\-b}
.I bootfile
] [
.B \-q
] [
.B \-r
]
.SH DESCRIPTION
.I 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 arguments,
.I named
will read the default boot file
.IR /etc/named.boot ,
read any initial data and listen for queries.
.PP
Options are:
.TP
.B \-d
Print debugging information.
A number after the ``d'' determines the level of
messages printed.
.TP
.B \-p
Use nonstandard port numbers.  The default is the standard port number
as returned by getservbyname(3) for service ``domain''.
The argument can specify two port numbers separated by a slash (``\fB/\fP'')
in which case the first port is that used when contacting remote servers,
and the second one is the service port bound by the local instance of
.IR named .
This is used mostly for debugging purposes.
.TP
.B \-b
Use an alternate boot file.  This is optional and allows you to
specify a file with a leading dash.
.TP
.B \-q
Trace all incoming queries if \fInamed\fP has been compiled with
\fIQRYLOG\fP defined.  \fINOTE:\fP this option is deprecated in favour
of the boot file directive ``options query-log''.
.TP
.B \-r
Turns recursion off in the server.  Answers can come only from local
(primary or secondary) zones.  This can be used on root servers.
\fINOTE:\fP this option is deprecated in favour
of the boot file directive ``options no-recursion''.
.PP
Any additional argument is taken as the name of the boot file.
If multiple boot files are specified, only the last is used.
.PP
The boot file contains information about where the name server is to get
its initial data.  
Lines in the boot file cannot be continued on subsequent lines.
The following is a small example:
.in +2m
.nf

;
;	boot file for name server
;
directory	/usr/local/adm/named

.ta \w'forwarders\ 'u +\w'6.32.128.IN-ADDR.ARPA\ 'u +\w'128.32.137.8 128.32.137.3\ 'u
; 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
limit	max-xfers 10
limit	datasize 64M
options	forward-only query-log fake-iquery

.DT
.fi
.in
The ``directory'' line causes the server to change its working directory to
the directory specified.  This can be important for the correct processing
of \s-1$INCLUDE\s+1 files in primary zone files.
.LP
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 ``root.cache'' file should be retrieved
periodically from \s-1FTP.RS.INTERNIC.NET\s+1 since it contains a list of
root servers, and this list changes periodically.
.LP
The first example ``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 RFC 883.  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
authoritative 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).
.LP
The first example ``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 continue
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
transferred 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.  If no file name is given, a temporary file will be used, and will
be deleted after each successful zone transfer.  This is not recommended
since it is a needless waste of bandwidth.  The second example ``secondary''
line states that the address-to-hostname mapping for the subnet 128.32.136
should be obtained from the same list of master servers as the previous zone.
.LP
The ``forwarders'' line specifies the addresses of sitewide servers that
will accept recursive queries from other servers.  If the boot file
specifies 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 ``forward-only'' 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 direct access
to the Internet, but wish to look up exterior names anyway.
.LP
The ``slave'' line (deprecated) is allowed for backward compatibility.  Its
meaning is identical to ``options forward-only''.
.LP
The ``sortlist'' line can be used to indicate networks that are to be
preferred over other 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.
.LP
The ``xfrnets'' directive (not shown) can be used to implement primitive
access control.  If this directive is given, then your name server will
only answer zone transfer requests from hosts which are on networks listed
in your ``xfrnets'' directives.  This directive may also be given as
``tcplist'' for compatibility with older, interim servers.
.LP
The ``include'' directive (not shown) can be used to process the contents
of some other file as though they appeared in place of the ``include''
directive.  This is useful if you have a lot of zones or if you have 
logical groupings of zones which are maintained by different people.
The ``include'' directive takes one argument, that being the name of the
file whose contents are to be included.  No quotes are necessary around
the file name.
.LP
The ``bogusns'' directive (not shown) tells \s-1BIND\s+1 that no queries
are to be sent to the specified name server addresses (which are specified
as dotted quads, not as domain names).  This is useful when you know that
some popular server has bad data in a zone or cache, and you want to avoid
contamination while the problem is being fixed.
.LP
The ``limit'' directive can be used to change \s-1BIND\s+1's internal limits,
some of which (\fBdatasize\fP, for example) are implemented by the system and
others (like \fBtransfers-in\fP) by \s-1BIND\s+1 itself.  The number following
the limit name can be scaled by postfixing a ``k,'' ``m,'' or ``g'' for
kilobytes, megabytes, and gigabytes respectively.
\fBdatasize\fP's argument sets the process data size enforced by the kernel.
\fINote:\fP not all systems provide a call to implement this -- on such
systems, the use of the \fBdatasize\fP parameter of ``limit'' will result in
a warning message.
\fBtransfers-in\fP's argument is the number of \fInamed-xfer\fP subprocesses
which \s-1BIND\s+1 will spawn at any one time.
\fBtransfers-per-ns\fP's argument is the maximum number of zone transfers to
be simultaneously initiated to any given remote name server.
.LP
The ``options'' directive introduces a boolean specifier that changes the
behaviour of \s-1BIND\s+1.  More than one option can be specified in a single
directive.  The currently defined options are as follows:
\fBno-recursion\fP, which will cause \s-1BIND\s+1 to answer with a referral
rather than actual data whenever it receives a query for a name it is not
authoritative for -- don't set this on a server that is listed in any host's
\fIresolv.conf\fP file;
\fBquery-log\fP, which causes all queries to be logged via
syslog(8) -- this is a lot of data, don't turn it on lightly;
\fBforward-only\fP, which causes the server to query only its forwarders --
this option is normally used on machine that wishes to run a server but for
physical or administrative reasons cannot be given access to the Internet;
and \fBfake-iquery\fP, which tells \s-1BIND\s+1 to send back a useless and
bogus reply to ``inverse queries'' rather than responding with an error --
this is helpful if you have a lot of microcomputers or SunOS hosts or both.
.LP
The ``max-fetch'' directive (not shown) is allowed for backward compatibility;
its meaning is identical to ``limit transfers-in''.
.PP
The master file consists of control information and a list of resource
records for objects in the zone of the forms:
.RS
.nf

$INCLUDE <filename> <opt_domain>
$ORIGIN <domain>
<domain> <opt_ttl> <opt_class> <type> <resource_record_data>

.fi
.RE
where
.I domain
is "." for root, "@" for the current origin, or a standard domain
name. If
.I 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
.I opt_domain
field is used to define an origin 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
.I opt_domain
field nor $ORIGIN statements in the included file modify the current origin
for this file.
The
.I opt_ttl
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
.I opt_class
field is the object address type; currently only one type is supported,
.BR IN ,
for objects connected to the DARPA Internet. 
The
.I type
field contains one of the following tokens; the data expected in the
.I resource_record_data
field is in parentheses.
.TP "\w'MINFO    'u"
A
a host address (dotted quad)
.IP NS
an authoritative name server (domain)
.IP MX
a mail exchanger (domain), preceded by a preference value (0..32767),
with lower numeric values representing higher logical preferences.
.IP CNAME
the canonical name for an alias (domain)
.IP 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 RFC 883)).
.IP NULL
a null resource record (no format or data)
.IP RP
a Responsible Person for some domain name (mailbox, TXT-referral)
.IP PTR
a domain name pointer (domain)
.IP HINFO
host information (cpu_type OS_type)
.PP
Resource records normally end at the end of a line,
but may be continued across lines between opening and closing parentheses.
Comments are introduced by semicolons and continue to the end of the line.
.PP
Note that there are other resource record types, not shown here.  You should
consult the \s-1BIND\s+1 Operations Guide (``\s-1BOG\s+1'') for the complete
list.  Some resource record types may have been standardized in newer RFC's
but not yet implemented in this version of \s-1BIND\s+1.
.PP
Each master zone file should begin with an SOA record for the zone.
An example SOA record is as follows:
.LP
.nf
@	IN	SOA	ucbvax.Berkeley.EDU. rwh.ucbvax.Berkeley.EDU. (
				1989020501	; serial
				10800	; refresh
				3600	; retry
				3600000	; expire
				86400 )	; minimum
.fi
.LP
The SOA specifies a serial number, which should be changed each time the
master file is changed.  Note that the serial number can be given as a
dotted number, but this is a \fIvery\fP unwise thing to do since the
translation 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 strategy in
the year 4294 (Greg.) but we're not worried about it.  Secondary servers
check the serial number at intervals 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 specifies the interval 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 time-to-live (``\s-1TTL\s+1'') used by records in the
file with no explicit time-to-live value.
.SH 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 complete information.
.sp
The following signals have the specified effect when sent to the
server process using the
.IR kill (1)
command.
.IP SIGHUP
Causes server to read named.boot and reload the database.  If the server
is built with the FORCED_RELOAD compile-time option, then SIGHUP will
also cause the server to check the serial number on all secondary zones.
Normally the serial numbers are only checked at the SOA-specified intervals.
.IP SIGINT
Dumps the current data base and cache to /var/tmp/named_dump.db
.IP SIGIOT
Dumps statistics data into /var/tmp/named.stats if the server is
compiled with -DSTATS.  Statistics data is appended to the file.  Some
systems use SIGABRT rather than SIGIOT for this.
.IP SIGSYS
Dumps the profiling data in /var/tmp if the server is compiled
with profiling (server forks, chdirs and exits).
.IP SIGTERM
Dumps the primary and secondary database files.
Used to save modified data on shutdown if the
server is compiled with dynamic updating enabled.
.IP SIGUSR1
Turns on debugging; each SIGUSR1 increments debug level.
(SIGEMT on older systems without SIGUSR1)
.IP SIGUSR2
Turns off debugging completely.
(SIGFPE on older systems without SIGUSR2)
.IP SIGWINCH
Toggles logging of all incoming queries via syslog(8)
(requires server to have been built with the QRYLOG option).
.SH FILES
.nf
.ta \w'/var/tmp/named_dump.db   'u
/etc/named.boot	name server configuration boot file
/etc/named.pid	the process id (/var/run/named.pid on newer systems)
/var/tmp/named.run	debug output
/var/tmp/named_dump.db	dump of the name server database
/var/tmp/named.stats	nameserver statistics data
.fi
.SH "SEE ALSO"
kill(1), gethostbyname(3), signal(2), 
resolver(3), resolver(5), hostname(7),
RFC 882, RFC 883, RFC 973, RFC 974, RFC 1033, RFC 1034, RFC 1035, RFC 1123,
\fIName Server Operations Guide for \s-1BIND\s+1\fR