Red Hat LINUX 7.2 Reference Manual page 232

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14.2.2 Zone Files
Zone files, which contain information about a particular namespace, are stored in the named working
directory. By default, this is /var/named. Each zone file is named according to the file option
data in the zone statement, usually in a way that relates to the domain in question and identifies the
file as containing zone data, such as example.com.zone.
Each zone file may contain directives and resource records. Directives tell the nameserver to do a
certain thing or apply a special setting to the zone. Resource records define the parameters of the
zone, assigning an identity within the zone's namespace to particular systems. Directives are optional,
but resource records are required to provide nameservice to that zone. All directives and resource
records should go on their own lines.
Comments can be placed after semicolon characters (;) in zone files.
Zone File Directives
Directives are identified by the leading $ character before the name of the directive and usually placed
at the top of the zone file.
The following directives are the most commonly used:
• $INCLUDE — Tells named to include another zone file in this zone file at the place where the
directive is used. This allows additional zone settings to be stored apart from the main zone file.
• $ORIGIN — Sets the domain name to be appended to any unqualified records, such as those that
only specify the host and nothing more.
For example, a zone file may contains the following line:
$ORIGIN domain.com
At this point, any names that are used in resource records and do not end in a trailing dot (.) will
have this domain name added to them. So, in other words, when the zone record is read by the
nameserver, the first line below will be interpreted as the second line:
ftp
ftp.domain.com.
IN
IN
The use of the $ORIGIN directive is unnecessary if you name the zone in
/etc/named.conf the same as the value you would assign to $ORI-
GIN. The zone's name is used as the $ORIGIN directive's value by de-
fault.
Chapter 14:Berkeley Internet Name Domain (BIND)
CNAME server1
CNAME server1.domain.com.
Note