path: root/contrib/bind/doc/man/named.8

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.\"	@(#)named.8	6.6 (Berkeley) 2/14/89
.\"
.Dd February 1, 1996
.Dt @INDOT_U@NAMED @SYS_OPS_EXT_U@ 
.Os BSD 4
.Sh NAME
.Nm @INDOT@named 
.Nd Internet domain name server (DNS)
.Sh SYNOPSIS
.Nm @INDOT@NAMED
.Op Fl d Ar debuglevel
.Op Fl p Ar port# 
.Oo Fl Po 
.Cm b Ns \&| Ns Cm c
.Pc
.Ar config_file
.Oc
.Op Fl f q r v
.Op Fl u Ar user_name
.Op Fl g Ar group_name
.Op Fl t Ar directory
.Op Fl w Ar directory
.Op Ar config_file
.Sh DESCRIPTION
.Ic 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,
.Ic named
will read the default configuration file
.Pa /etc/named.conf ,
read any initial data, and listen for queries.  A 
.Ar config_file
argument given at the end of the command line will override any
.Ar config_file
specified by using the
.Dq Fl b
or
.Dq Fl c
flags.
.Pp
.Sy NOTE:
Several of 
.Nm named Ns 's
options, and much more of its behaviour, can be controlled in the configuration 
file.  Please refer to the configuration file guide included with this 
.Sy BIND
distribution for further information.
.Pp
Options are:
.Bl -tag -width Fl
.It Fl d Ar debuglevel
Print debugging information.
The 
.Ar debuglevel 
is a number determines the level of messages printed.  If negative,
.Ar debuglevel
is set to 
.Dq 1 .
.Pp
.Sy NOTE:
The new debugging framework is considerably more sophisticated than it
was in older versions of 
.Nm @INDOT@NAMED .
The configuration file's
.Dq Li logging
statement allows for multiple, distinct levels of debugging for each of
a large set of categories of events (such as queries, transfers in or out,
etc.).  Please refer to the configuration file guide included with this 
.Sy BIND
distribution for further information about these extensive new capabilities.
.It Fl p Ar port#
Use the specified remote port number; this is the port number to which 
.Nm @INDOT@NAMED
will send queries.  The default value is the standard port number, i.e.,
the port number returned by 
.Xr getservbyname @LIB_NETWORK_EXT@ 
for service 
.Dq Li domain .
.Pp
.Sy NOTE:
Previously, the syntax
.Dq Fl p Ar port# Ns Op Ar \&/localport#
was supported; the first port was that used when contacting 
.Em remote 
servers, and the second one was the service port bound by the 
.Em local 
instance of
.Nm @INDOT_U@NAMED .
The current usage is equivalent to the old usage without the 
.Ar localport#
specified; this functionality can be specified with the 
.Dq Li listen-on
clause of the configuration file's
.Dq Li options
statement.
.It Xo Fl Po 
.Cm b Ns \&| Ns Cm c
.Pc Ar config_file
.Xc
Use an alternate 
.Ar config_file ;
this argument is overridden by any 
.Ar config_file
which is specified at the end of the command line.
The default value is
.Pa /etc/named.conf .
.It Fl f
Run this process in the foreground; don't 
.Xr fork @SYSCALL_EXT@
and daemonize.  (The default is to daemonize.)
.It Fl q
Trace all incoming queries if 
.Nm @INDOT_U@NAMED 
has been compiled with
.Li QRYLOG 
defined.  
.Pp
.Sy NOTE: 
This option is deprecated in favor of the
.Dq Li queries
.Em logging category 
of the configuration file's
.Dq Li logging 
statement; for more information, please refer to the configuration file guide 
included with this distribution of 
.Sy BIND .
.It Fl 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.
.Pp
.Sy NOTE: 
This option can be overridden by and is deprecated in favor of the
.Dq Li recursion 
clause of the configuration file's
.Dq Li options
statement.
.It Fl v
Report the version and exit. 
.It Fl u Ar user_name
Specifies the user the server should run as after it initializes.  The value
specified may be either a username or a numeric user id.  If the
.Dq Fl g
flag is not specified, 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).
.Pp
.It Fl g Ar group_name
Specifies the group the server should run as after it initializes.  The value
specified may be either a groupname or a numeric group id.
.Pp
.It Fl t Ar directory
Specifies the directory the server should chroot() into as soon as it is
finshed processing command line arguments.
.Pp
.It Fl w Ar directory
Sets the working directory of the server.  The
.Dq Li directory 
clause of the configuration file's
.Dq Li options
statement overrides any value specified on the command line.
The default working directory is the current directory
.Pq Dq \&. .
.El
.Pp
Any additional argument is taken as the name of the configuration file, for
compatibility with older implementations; as noted above, this argument
overrides any
.Ar config_file
specified by the use of the
.Dq Fl b
or 
.Dq Fl c
flags.  If no further argument is given, then the default configuration file
is used
.Pq Pa /etc/named.conf .
.Ss Master File Format
The master file consists of control information and a list of resource
records for objects in the zone of the forms:
.Bd -literal -offset indent
$INCLUDE <filename> <opt_domain>
$ORIGIN <domain>
$TTL <ttl>
<domain> <opt_ttl> <opt_class> <type> <resource_record_data>
.Ed
.Pp
where:
.Bl -tag -width "opt_domain  " 
.It Ar domain
is 
.Dq Li \&. 
for root, 
.Dq Li @ 
for the current origin, or a standard domain name. If
.Ar domain
is a standard domain name that does 
.Em not 
end with 
.Dq Li \&. , 
the current origin is appended to the domain. Domain names ending with 
.Dq Li \&.
are unmodified.
.It Ar opt_domain
This field is used to define an origin for the data in an included file.
It is equivalent to placing an 
.Li $ORIGIN 
statement before the first line of the included file.  The field is optional.
Neither the 
.Ar opt_domain
field nor 
.Li $ORIGIN 
statements in the included file modify the current origin for this file.
.It Ar ttl
A integer number that sets the default time-to-live for future records without
an explicit ttl.
.It Ar 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 occured then the SOA minimum value is used and a
warning is generated.
.It Ar opt_class
The object address type; currently only one type is supported,
.Dv IN ,
for objects connected to the DARPA Internet. 
.It Ar type
This field contains one of the following tokens; the data expected in the
.Ar resource_record_data
field is in parentheses:
.Bl -tag -width "HINFO    "  -offset indent
.It Dv A
a host address (dotted-quad IP address)
.It Dv NS
an authoritative name server (domain)
.It Dv MX
a mail exchanger (domain), preceded by a preference value (0..32767),
with lower numeric values representing higher logical preferences.
.It Dv CNAME
the canonical name for an alias (domain)
.It Dv 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
and RFC 2308)).
.It Dv NULL
a null resource record (no format or data)
.It Dv RP
a Responsible Person for some domain name (mailbox, TXT-referral)
.It Dv PTR
a domain name pointer (domain)
.It Dv HINFO
host information (cpu_type OS_type)
.El
.El
.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
.Sy NOTE:
There are other resource record types not shown here.  You should
consult the 
.Sy BIND 
Operations Guide 
.Pq Dq 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 
.Sy BIND .
.Ss SOA Record Format
Each master zone file should begin with an SOA record for the zone.
An example SOA record is as follows:
.Bd -literal
@	IN	SOA	ucbvax.Berkeley.EDU. rwh.ucbvax.Berkeley.EDU. (
				1989020501	; serial
				10800	; refresh
				3600	; retry
				3600000	; expire
				86400 )	; minimum
.Ed
.Pp
The SOA specifies a serial number, which should be incremented each time the
master file is changed.  Note that the serial number can be given as a
dotted number, but this is a 
.Em very 
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, but we're not worried about it.)
.Pp
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 cache time-to-live for negative answers (RFC 2308).
.Sh NOTES
The boot file directives 
.Dq Li domain 
and 
.Dq Li 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.
.Pp
The following signals have the specified effect when sent to the
server process using the
.Xr kill @CMD_EXT@
command:
.Pp
.Bl -tag -width "SIGWINCH" 
.It Dv SIGHUP
Causes server to read 
.Pa named.conf 
and reload the database.  If the server
is built with the 
.Li FORCED_RELOAD 
compile-time option, then 
.Dv 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.
.It Dv SIGINT
Dumps the current data base and cache to 
.Dq Pa /var/tmp/named_dump.db 
or the value of 
.Dv _PATH_DUMPFILE .
.It Dv SIGILL
Dumps statistics data into 
.Pa named.stats 
if the server is compiled with 
.Li -DSTATS .  
Statistics data is appended to the file.
.It Dv SIGSYS
Dumps the profiling data in 
.Pa /var/tmp 
if the server is compiled with profiling (server forks, chdirs and exits).
.It Dv SIGTERM
Saves any modified dynamic zones to the file system, and shuts down the server.
.It Dv SIGUSR1
Turns on debugging; each 
.Dv SIGUSR1 
increments debug level.
.Po Dv SIGEMT 
on older systems without 
.Dv SIGUSR1 .
.Pc 
.It Dv SIGUSR2
Turns off debugging completely.
.Po Dv SIGFPE 
on older systems without 
.Dv SIGUSR2 .
.Pc
.It Dv SIGWINCH
Toggles logging of all incoming queries via 
.Xr syslog @SYS_OPS_EXT@
(requires server to have been built with the 
.Li QRYLOG 
option).
.El
.Sh FILES
.Bl -tag -width "/var/tmp/named_dump.db (_PATH_DUMPFILE)   " -compact
.It Pa /etc/named.conf
default name server configuration file
.It Pa /var/run/named.pid Pq Dv _PATH_PIDFILE
the process id 
.It Pa /var/tmp/named_dump.db Pq Dv _PATH_DUMPFILE
dump of the name server database
.It Pa /var/tmp/named.run Pq file:  Dv _PATH_DEBUG
debug output
.It Pa /var/tmp/named.stats Pq file:  Dv _PATH_STATS
nameserver statistics data
.El
.Sh SEE ALSO
.Xr gethostbyname @LIB_NETWORK_EXT@ ,
.Xr hostname @DESC_EXT@ ,
.Xr kill @CMD_EXT@ ,
.Xr resolver @LIB_NETWORK_EXT@ , 
.Xr resolver @FORMAT_EXT@ , 
.Xr signal @SYSCALL_EXT@ ,
RFC 882, RFC 883, RFC 973, RFC 974, RFC 1033, RFC 1034, RFC 1035, RFC 1123,
RFC 2308
.Dq Name Server Operations Guide for Sy BIND