master.html   [plain text]


<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN">
<HTML>
<HEAD>
  <TITLE>Master File Format</TITLE>
</HEAD>

<BODY>
<H2>BIND Configuration Guide -- Master File Format</H2>

<HR>

<P>
The Master File Format was initially defined in
<A HREF=http://www.ietf.org/rfc/rfc1035.txt>RFC 1035</A>
and has subsequently been extended. 
<P>
While the Master File Format is class independent all records in a 
Master File must be of the same class.

<H3>Master File Directives</H3>
<H4>$ORIGIN</H4>
Syntax: <CODE>$ORIGIN &lt;domain-name&gt; [&lt;comment&gt;]</CODE>
<P>
<CODE>$ORIGIN</CODE> set the domain name that will be appended to any
unqualified records.
When a zone is first read in there is an implict <CODE>$ORIGIN</CODE>
&lt;zone-name&gt;.
The current <CODE>$ORIGIN</CODE> is appended to the domain specified in the
<CODE>$ORIGIN</CODE> argument if it is not absolute.

<PRE>
$ORIGIN EXAMPLE.
$ORIGIN MYZONE
WWW	CNAME	MAIN-SERVER
</PRE>
is equivlent to
<PRE>
WWW.MYZONE.EXAMPLE. CNAME MAIN-SERVER.MYZONE.EXAMPLE.
</PRE>

<H4>$INCLUDE</H4>
Syntax: <CODE>$INCLUDE &lt;filename&gt; [&lt;origin&gt;] [&lt;comment&gt;]</CODE>
<P>
Read and process the file filename as if it was included into the file at this
point.  If origin is specified the file is processed with <CODE>$ORIGIN</CODE>
set to that value otherwise the current <CODE>$ORIGIN</CODE> is used.
<I>NOTE: The  behaviour when &lt;origin&gt; is specified differs from that
described in 
<A HREF=http://www.ietf.org/rfc/rfc1035.txt>RFC 1035</A>.</I>
<P>
The origin and current domain revert to the values they were prior to the
<CODE>$INCLUDE</CODE> once the file has been read.
<H4>$TTL</H4>
Syntax: <CODE>$TTL &lt;default-ttl&gt; [&lt;comment&gt;]</CODE>
<P>
Set the default Time To Live (TTL) for subsequent records with undefined
TTL's. Valid TTL's are of the range 0-2147483647.
<P>
<CODE>$TTL</CODE> is defined in
<A HREF=http://www.ietf.org/rfc/rfc2308.txt>RFC 2308</A>.
<H3>BIND Master File Extentions</H3>
<H4>$GENERATE</H4>
Syntax: <CODE>$GENERATE &lt;range&gt; &lt;lhs&gt; &lt;type&gt; &lt;rhs&gt;
[&lt;comment&gt;]</CODE>
<P>
<CODE>$GENERATE</CODE> is used to create a series of resource records
that only differ from each other by an iterator.  <CODE>$GENERATE</CODE>
can be used to easily generate the sets of records required to support
sub /24 reverse delegations described in 
<A HREF=http://www.ietf.org/rfc/rfc2317.txt>RFC 2317: Classless IN-ADDR.ARPA delegation</A>.

<PRE>
$ORIGIN 0.0.192.IN-ADDR.ARPA.
$GENERATE 1-2 0 NS SERVER$.EXAMPLE.
$GENERATE 1-127 $ CNAME $.0
</PRE>
is equivalent to
<PRE>
0.0.0.192.IN-ADDR.ARPA NS SERVER1.EXAMPLE.
0.0.0.192.IN-ADDR.ARPA NS SERVER2.EXAMPLE.
1.0.0.192.IN-ADDR.ARPA CNAME 1.0.0.0.192.IN-ADDR.ARPA.
2.0.0.192.IN-ADDR.ARPA CNAME 2.0.0.0.192.IN-ADDR.ARPA.
...
127.0.0.192.IN-ADDR.ARPA CNAME 127.0.0.0.192.IN-ADDR.ARPA.
</PRE>
<DL>
<DT>range</DT>
<DD>
This can be one of two forms:
<I>start</I>-<I>stop</I>
or
<I>start</I>-<I>stop</I>/<I>step</I>.  If the first form is
used then step is set to 1.  All of start, stop and step must be positive.
<DT>lhs</DT>
<DD>
Lhs describes the owner name of the resource records to be created.
Any single $ symbols within the LHS side are replaced by the iterator value.
To get a $ in the output use \$.  If the lhs is not absolute
the current $ORIGIN is appended to the name, when appropriate.
You can also apply an offset to the iterator by using ${offset} where
offset is a decimal value to add to the iterator.
And you can also change the format of the iterator by using a printf
like string.  The format is ${offset,width,radix} where offset is as before
(use 0 for no change), width is the minimum field width (always zero padded)
radix is one of d, o, x, or X to change the radix to decimal, octal, hex, or hex
with capital letters.
The default is ${0,1,d}.
For example: ${16,3} will add 16 to the iterator and be replaced by
a 3 digit decimal representation.  ${0,2,x} will be replaced by a 2 digit
hex representation.  To get a { character inserted into the text
immediately after the iterator, use $\{.
<DT>type</DT>
<DD>
At present the only supported types are A, AAAA, PTR, CNAME and NS.
<DT>rhs</DT>
<DD>
Rhs is the data. It is processed similarly to the lhs.
<DD>
</DL>
<H2>Resource Records</H2>
Syntax: <CODE>{&lt;domain&gt;|@|&lt;blank&gt;}
[&lt;ttl&gt;] [&lt;class&gt;] &lt;type&gt; &lt;rdata&gt;
[&lt;comment&gt;]</CODE>
<P>
All resource records have the same basic syntax.
<DL>
<DT><CODE>domain</CODE></DT>
<DD>
Specify the domain name for this record.  If it is not absolute the
current <CODE>$ORIGIN</CODE> is appended.
<DT><CODE>@</CODE></DT>
<DD>
Use the current <CODE>$ORIGIN</CODE> for the domain name for this record.
<DT><CODE>blank</CODE></DT>
<DD>
Use the last specified domainname.
<DT><CODE>ttl</CODE></DT>
<DD>
This specifies how long this record will be cached by caching servers.
The valid range is 0-2147483647.
<DT><CODE>class</CODE></DT>
<DD>
Specify the class of this record.  This is usually redundent as the
class of a zone is specfied in the configuration file prior to reading
the zone file.
<DT><CODE>type</CODE></DT>
<DD>
Specify the type of this record. This describes the contents of the rdata
section.
<DT><CODE>rdata</CODE></DT>
<DD>
This is the value of the resource record.
</DL>
<H2>Time Values: Alternate Specification format (BIND Enhancement)</H2>
<P>
Many time values within the MASTER file may be specified in multiples
of weeks, days, hours, minutes and seconds rather than just seconds.
<P>
The format for this is <CODE>#w#d#h#m#s</CODE>. To specify 1 week you would
use <CODE>1w</CODE> or two weeks and 1 hour <CODE>2w1h</CODE>.
<P>
This format applies to TTL values, and SOA REFRESH, RETRY, EXPIRE and MINIMUM
values.
</P>
</BODY>
</HTML>