NAMED(8) MachTen Programmer’s Manual NAMED(8)

NAME
named - Internet domain name server

SYNOPSIS
named [ -d debuglevel ] [ -p port# ] [{-b} bootfile ] [ -q
] [ -r ]

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 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 returned by getservby-
name(3) for service ‘‘domain’’.

-b Use an alternate boot file. This is optional and
allows you to specify a file with a leading dash.

-q Trace all incoming queries if named has been com-
piled with QRYLOG defined.

-r Turns recursion off in the server. Answers can
come only from local (primary or secondary) zones.
This can be used on root servers.

Any additional argument is taken as the name of the boot
file. If multiple boot files are specified, only the last
is used.

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:

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

; 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 processing 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 ‘‘berke-
ley.edu.zone’’. There can be more than one ‘‘cache’’ file
specified. The ‘‘root.cache’’ file should be retrieved
periodically from FTP.RS.INTERNIC.NET since it contains a
list of root servers, and this list changes periodically.

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
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 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).

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 try-
ing 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 trans-
ferred zone. The name server will load the zone from this
backup file if it exists when it boots, providing a com-
plete 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 success-
ful zone transfer. This is not recommended since it is a
needless waste of bandwidth. The second example ‘‘sec-
ondary’’ 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.

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 with-
out 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 forwarders. 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 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.

The ‘‘xfrnets’’ directive (not shown) can be used to
implement primative access control. If this directive is
given, then your name server will only answer zone trans-
fer requests from hosts which are on networks listed in
your ‘‘xfrnets’’ directives. This directive may also be
given as ‘‘tcplist’’ for compatibility with older, inter-
rim servers.

The ‘‘include’’ directive (not shown) can be used to pro-
cess 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 peo-
ple. 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.

The ‘‘bogusns’’ directive (not shown) tells BIND 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.

The ‘‘max-fetch’’ directive (not shown) can be used to
override the default limit (which is 10) to the number of
named-xfer subprocesses which BIND can spawn at any one
time.

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 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
opt_domain field nor $ORIGIN statements in the included
file modify the current origin for this file. The 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 opt_class
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 resource_record_data
field is in parentheses.

A a host address (dotted quad)

NS an authoritative name server (domain)

MX a mail exchanger (domain), preceded by a prefer-
ence 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 address of maintainer, a
serial number and the following parameters in
seconds: refresh, retry, expire and minimum TTL
(see RFC883)).

NULL a null resource record (no format or data)

RP a Responsible Person for some domain name (mail-
box, TXT-referral)

PTR a domain name pointer (domain)

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. Comments are introduced by semicolons and
continue to the end of the line.

Note that 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.

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. (
1989020501 ; serial
10800 ; refresh
3600 ; retry
3600000 ; expire
86400 ) ; minimum

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 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
(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 con-
tacted 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 (‘‘TTL’’) 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 implementa-
tion of suffixing for partially qualified domain names.
The prior mechanisms could fail under a number of situa-
tions, 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.boot and reload
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.

SIGINT Dumps current data base and cache to
/var/tmp/named_dump.db

SIGIOT Dumps statistics data into /var/tmp/named.stats if
the server is compiled -DSTATS. Statistics data is
appended to the file. Some systems use SIGABRT
rather than SIGIOT for this.

SIGSYS Dumps the profiling data in /var/tmp if the server
is compiled 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 dynamic updating enabled.

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(8) (requires server to have been built with the
QRYLOG option).

FILES
/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

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, Name Server
Operations Guide for BIND

MachTen April 17, 1993 5