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The name server uses several files to load its data base.
This section covers the files and their formats needed for \fInamed\fP.
This is the file that is first read when \fInamed\fP starts up.
This tells the server what type of server it is,
zones it has authority over and where to get its initial data.
The default location for this file is \fI/\|etc\|/\|named\|.\|boot\fP\|.
However this can be changed
by setting the \fIBOOTFILE\fP variable when you compile \fInamed\fP
the location on the command line when \fInamed\fP is started up.
A default domain may be specified for the nameserver
.ta 0.5i +\w`secondary `u +\w`berkeley.edu `u +.5i +.5i
\fIdomain Berkeley\fP\fB\|.\|\fP\fIEdu\fP
The name server uses this information when it receives a query for a
name without a ``\fB.\fP'' that is not known.
When it receives one of these queries, it appends the name in the second
This is an obsolete facility which will be removed from future releases.
The directory line specifies the directory in which the nameserver should
run, allowing the other file names in the boot file to use relative
.ta 0.5i +\w`secondary `u +\w`berkeley.edu `u +.5i +.5i
\fIdirectory /usr/local/domain\fP
If you have more than a couple of named files to be maintained,
you may wish to place the named files in a directory such as
/usr/local/domain and adjust the directory command properly.
The main purposes of this command are to make sure named is
in the proper directory when trying to include files by relative
path names with $Include and to allow named to run in a location
that is reasonable to dump core if it feels the urge.
The line in the boot file that designates the server as a primary server
for a zone looks as follows:
.ta 0.5i +\w`secondary `u +\w`berkeley.edu `u +.5i +.5i
\fIprimary Berkeley\fP\fB\|.\|\fP\fIEdu ucbhosts\fP
The first field specifies that the server is a primary one for the zone
stated in the second field.
The third field is the name of the file from which the data is read.
The line for a secondary server is similar to the primary except
that it lists addresses of other servers (usually primary servers)
from which the zone data will be obtained.
.ta 0.5i +\w`secondary `u +\w`berkeley.edu `u +.5i +.5i
\fIsecondary Berkeley\fP\fB\|.\|\fP\fIEdu 128\fP\fB.\fP\fI32\fP\fB.\fP\fI0\fP\fB.\fP\fI10 \fP\fI128\fP\fB.\fP\fI32\fP\fB.\fP\fI0\fP\fB.\fP\fI4\fP \fIucbhosts.bak\fP
The first field specifies that the server is a secondary master server for
the zone stated in the second field.
The two network addresses
specify the name servers that are primary for the zone.
The secondary server gets its data across the network from the listed servers.
Each server is tried in the order listed until it successfully receives the data
If a filename is present after the list of primary servers, data for the zone
will be dumped into that file as a backup.
When the server is first started, the data are loaded from the backup file
if possible, and a primary server is then consulted to check that the zone
.sh 3 "Caching Only Server"
You do not need a special line to designate that a server is a caching server.
What denotes a caching only server is the absence of authority
lines, such as \fIsecondary\fP or \fIprimary\fP in the boot file.
All servers should have a line as follows in the boot file to
prime the name servers cache:
\fIcache \fP\fB.\fP\fI root\fP\fB.\fP\fIcache\fP
All cache files listed will be read in at named boot time and
any values still valid will be reinstated in the cache and the root
nameserver information in the cache files will always be used.
For information on cache file see section on \fICache Initialization\fP.
Any server can make use of \fIforwarders\fP. A \fIforwarder\fP is another
server capable of processing recursive queries that is willing to try
resolving queries on behalf of other systems. The \fIforwarders\fP
command specifies forwarders by internet address as follows:
\fIforwarders \fI128\fP\fB.\fP\fI32\fP\fB.\fP\fI0\fP\fB.\fP\fI10 \fP\fI128\fP\fB.\fP\fI32\fP\fB.\fP\fI0\fP\fB.\fP\fI4\fP
There are two main reasons
for wanting to do so. First, the other systems may not have full network
access and may be prevented from sending any IP packets into the rest of
the network and therefore must rely on a forwarder which does have
access to the full net. The second reason is that the forwarder sees
a union of all queries as they pass through his server and therefore he
builds up a very rich cache of data compared to the cache in a typical
workstation nameserver. In effect, the \fIforwarder\fP becomes a meta-cache
that all hosts can benefit from, thereby reducing the total number of queries
from that site to the rest of the net.
Slave mode is used if the use of forwarders is the only possible way
to resolve queries due to lack of full net access or if you wish to prevent
the nameserver from using other than the listed forwarders.
Slave mode is activated by placing the simple command
in the bootfile. If \fIslave\fP is used, then you must specify forwarders.
When in slave mode, the server will forward each query to each of the
forwarders until an answer is found or the list of forwarders is
To set up a host that will use a remote server instead of a local
server to answer queries, the file \fI/\|etc/\|resolv\|.\|conf\fP
This file designates the name servers on the network that should
It is not advisable to create this file if you have a local server
running. If this file exists it is read almost every time
\fIgethostbyname\|()\fP or \fIgethostbyaddr\|()\fP is called.
.sh 2 "Cache Initialization"
The name server needs to know the servers that are the authoritative
name servers for the root domain of the network.
To do this we have to prime the name server's cache with the addresses
of these higher authorities.
The location of this file is specified in the boot file.
This file uses the Standard Resource Record Format (aka. Masterfile Format)
.sh 2 "Domain Data Files"
There are three standard files for specifying the data for a
domain. These are \fInamed\|.\|local\fP, \fIhosts\fP and \fIhost\|.\|rev\fP.
These files use the Standard Resource Record Format covered later
This file specifies the address for the local loopback interface,
better known as \fIlocalhost\fP with the network address 127.0.0.1.
The location of this file is specified in the boot file.
This file contains all the data about the machines in this zone.
The location of this file is specified in the boot file.
This file specifies the IN-ADDR\|.\|ARPA domain.
This is a special domain for allowing address to name mapping.
As internet host addresses do not fall within domain boundaries,
this special domain was formed to allow inverse mapping.
The IN-ADDR\|.\|ARPA domain has four
labels preceding it. These labels correspond to the 4 octets of
All four octets must be specified even if an octets is zero.
The Internet address 128.32.0.4 is located in the domain
4\|.\|0\|.\|32\|.\|128\|.\|IN-ADDR\|.\|ARPA.
This reversal of the address is awkward to read but allows
for the natural grouping of hosts in a network.
.sh 2 "Standard Resource Record Format"
The records in the name server data files are called resource records.
The Standard Resource Record Format (RR) is specified in RFC1035.
The following is a general description of these records:
\fI{name} {ttl} addr-class Record Type Record Specific data\fP
Resource records have a standard format shown above.
The first field is always the name of the domain record
and it must always start in column 1.
For some RR's the name may be left blank;
in that case it takes on the name of the previous RR.
The second field is an optional time to live field.
This specifies how long this data will be stored in the data base.
By leaving this field blank the default time to live is specified
in the \fIStart Of Authority\fP resource record (see below).
The third field is the address class; currently, only one class is supported:
\fIIN\fP for internet addresses and other information.
The fourth field states the type of the resource record.
The fields after that are dependent on the type of the RR.
Case is preserved in names and data fields when loaded into the name server.
All comparisons and lookups in the name server data base are case insensitive.
The following characters have special meanings:
A free standing dot in the name field refers to the current domain.
A free standing @ in the name field denotes the current origin.
Two free standing dots represent the null domain name of the root when used in
Where X is any character other than a digit (0-9),
quotes that character so that its special meaning does not apply.
For example, ``\e.'' can be used to place a dot character in a label.
Where each D is a digit, is the octet corresponding to the
decimal number described by DDD.
The resulting octet is assumed to be text and
is not checked for special meaning.
Parentheses are used to group data that crosses a line.
In effect, line terminations are not recognized within parentheses.
Semicolon starts a comment; the remainder of the line is ignored.
An asterisk signifies wildcarding.
Most resource records will have the current origin appended to names if they
are not terminated by a ``\fB.\fP''.
This is useful for appending the current domain name to the data,
such as machine names, but may cause problems where you do not want
A good rule of thumb is that, if the name is not in the domain for which
you are creating the data file, end the name with a ``\fB.\fP''.
An include line begins with $INCLUDE, starting in column 1,
and is followed by a file name.
particularly useful for separating different types of data into multiple files.
$INCLUDE /usr/named/data/mailboxes
The line would be interpreted as a request to load the file
\fI/usr/named/data/mailboxes\fP.
The $INCLUDE command does not cause data to be loaded into a
different zone or tree. This is simply a way to allow data for a
given zone to be organized in separate files. For example,
mailbox data might be kept separately from host data using this
The origin is a way of changing the origin in a data file.
The line starts in column 1, and is followed by a domain origin.
This is useful for putting more then one domain in a data file.
.sh 3 "SOA - Start Of Authority"
\fIname {ttl} addr-class SOA Origin Person in charge\fP
@ IN SOA ucbvax\fB.\fPBerkeley\fB.\fPEdu\fB.\fP kjd\fB.\fPucbvax\fB.\fPBerkeley\fB.\fPEdu\fB.\fP (
The \fIStart of Authority, SOA,\fP record designates the start of a zone.
The name is the name of the zone.
Origin is the name of the host on which this data file resides.
Person in charge is the mailing address for the person responsible
The serial number is the version number of this data file,
this number should be incremented whenever a change is made to the data.
The name server cannot handle numbers over 9999 after the decimal point.
The refresh indicates how often, in seconds, a secondary name servers
is to check with the primary name server to see if an update is needed.
The retry indicates how long, in seconds, a secondary server is to retry
after a failure to check for a refresh.
Expire is the upper limit, in seconds, that a secondary name server
is to use the data before it expires for lack of getting a refresh.
Minimum is the default number of seconds to be used for the time to live
field on resource records.
There should only be one \fISOA\fP record per zone.
\fI{name} {ttl} addr-class NS Name servers name\fP
IN NS ucbarpa\fB\|.\|\fPBerkeley\fB\|.\|\fPEdu\fB.\fP
The \fIName Server\fP record, \fINS\fP, lists a name server responsible
The first name field lists the domain that is serviced by
There should be one \fINS\fP record for each Primary Master
\fI{name} {ttl} addr-class A address\fP
ucbarpa IN A 128\fB.\fP32\fB.\fP0\fB.\fP4
IN A 10\fB.\fP0\fB.\fP0\fB.\fP78
The \fIAddress\fP record, \fIA\fP, lists the address for a given machine.
The name field is the machine name and the address is the network address.
There should be one \fIA\fP record for each address of the machine.
.sh 3 "HINFO - Host Information"
\fI{name} {ttl} addr-class HINFO Hardware OS\fP
\fIHost Information\fP resource record, \fIHINFO\fP, is for host specific data.
This lists the hardware and operating system that are running at
It should be noted that only a single space separates the hardware info
and the operating system info.
If you want to include a space in the machine name you must quote the name.
There should be one \fIHINFO\fP record for each host.
.sh 3 "WKS - Well Known Services"
\fI{name} {ttl} addr-class WKS address protocol list of services\fP
IN WKS 128\fB.\fP32\fB.\fP0\fB.\fP10 UDP who route timed domain
IN WKS 128\fB.\fP32\fB.\fP0\fB.\fP10 TCP ( echo telnet
The \fIWell Known Services\fP record, \fIWKS\fP,
describes the well known services
supported by a particular protocol at a specified address.
The list of services and port numbers come from the list of services
specified in \fI/etc/services.\fP
There should be only one \fIWKS\fP record per protocol per address.
.sh 3 "CNAME - Canonical Name"
\fIaliases {ttl} addr-class CNAME Canonical name\fP
\fICanonical Name\fP resource record, \fICNAME\fP, specifies an
alias for a canonical name.
An alias should be the only record associated with the alias name;
all other resource records should be
associated with the canonical name and not with the alias.
Any resource records that include a domain name as their value (e.g. NS or MX)
should list the canonical name, not the alias.
.sh 3 "PTR - Domain Name Pointer"
\fIname {ttl} addr-class PTR real name\fP
7.0 IN PTR monet\fB\|.\|\fPBerkeley\fB\|.\|\fPEdu\fB\|.\fP
A \fIDomain Name Pointer\fP record, \fIPTR\fP, allows special names
to point to some other location in the domain.
The above example of a \fIPTR\fP record is used in setting up reverse pointers
for the special \fIIN-ADDR\fP\fB\|.\|\fP\fIARPA\fP domain. This line is from the example
\fIPTR\fP names should be unique to the zone.
\fIname {ttl} addr-class MB Machine \fP
miriam IN MB vineyd\fB.\fPDEC\fB.\fPCOM\fB.\fP
\fIMB\fP is the \fIMailbox\fP record.
This lists the machine where a user wants to receive mail.
The name field is the users login; the machine field denotes the machine
to which mail is to be delivered.
Mail Box names should be unique to the zone.
(These records are currently for experimental use only.)
.sh 3 "MR - Mail Rename Name"
\fIname {ttl} addr-class MR corresponding MB\fP
Postmistress IN MR miriam
\fIMail Rename, MR,\fP can be used to list aliases for a user.
The name field lists the alias for the name listed in the fourth field,
which should have a corresponding \fIMB\fP record.
(These records are currently for experimental use only.)
.sh 3 "MINFO - Mailbox Information"
\fIname {ttl} addr-class MINFO requests maintainer\fP
BIND IN MINFO BIND-REQUEST kjd\fB\|.\|\fPBerkeley\fB\|.\|\fPEdu\fB\|.\fP
\fIMail Information\fP record, \fIMINFO\fP, creates a mail
group for a mailing list.
This resource record is usually associated with a mail group \fIMail Group\fP,
but may be used with a \fIMail Box\fP record.
The \fIname\fP specifies the name of the mailbox.
is where mail such as requests to be added to a mail group should be sent.
The \fImaintainer\fP is a mailbox that should receive error messages.
This is particularly appropriate for mailing lists when
errors in members names should be reported to a person other than
(These records are currently for experimental use only.)
.sh 3 "MG - Mail Group Member"
\fI{mail group name} {ttl} addr-class MG member name\fP
\fIMail Group, MG\fP lists members of a mail group.
(These records are currently for experimental use only.)
An example for setting up a mailing list is as follows:
Bind IN MINFO Bind-Request kjd\fB\|.\|\fPBerkeley\fB\|.\|\fPEdu\fB\|.\fP
IN MG Ralph\fB\|.\|\fPBerkeley\fB\|.\|\fPEdu\fB\|.\fP
IN MG Zhou\fB\|.\|\fPBerkeley\fB\|.\|\fPEdu\fB\|.\fP
IN MG Painter\fB\|.\|\fPBerkeley\fB\|.\|\fPEdu\fB\|.\fP
IN MG Riggle\fB\|.\|\fPBerkeley\fB\|.\|\fPEdu\fB\|.\fP
IN MG Terry\fB\|.\|\fPpa\fB\|.\|\fPXerox\fB\|.\|\fPCom\fB\|.\fP
.sh 3 "MX - Mail Exchanger"
\fIname {ttl} addr-class MX preference value mailer exchanger\fP
Munnari\fB\|.\|\fPOZ\fB\|.\|\fPAU\fB\|.\fP IN MX 0 Seismo\fB\|.\|\fPCSS\fB\|.\|\fPGOV\fB\|.\fP
*\fB\|.\|\fPIL\fB\|.\fP IN MX 0 RELAY\fB\|.\|\fPCS\fB\|.\|\fPNET\fB\|.\fP
\fIMail Exchanger\fP records, \fIMX\fP, are used to specify a
machine that knows how to deliver
mail to a machine that is not directly connected to the network.
In the first example, above, Seismo\fB\|.\|\fPCSS\fB\|.\|\fPGOV\fB\|.\fP is a mail gateway
deliver mail to Munnari\fB\|.\|\fPOZ\fB\|.\|\fPAU\fB\|.\fP but other machines
on the network can not deliver mail directly to Munnari.
These two machines may have a private connection or use a different
The preference value is the order that a mailer should follow
when there is more then one way to deliver mail to a single machine.
See RFC974 for more detailed information.
Wildcard names containing the character ``*'' may be
used for mail routing with \fIMX\fP records.
There are likely to be servers on the network
that simply state that any mail to a domain is to be routed through a relay.
Second example, above, all mail to hosts in the domain IL is routed through RELAY.CS.NET.
This is done by creating a wildcard resource record,
which states that *.IL has an \fIMX\fP
The following section contains sample files for the name server.
This covers example boot files for the different types of servers
and example domain data base files.
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