BIND Configuration File Guide - Variable Definitions

Syntax Variables

The following elements are used throughout the BIND configuration file documentation. Elements that are associated with only one statement are described only in the section that discusses that statement.

acl_name

The name of an address match list, as defined by the acl statement.

address_match_list

A list of one or more ip_address, ip_prefix key_id or acl_name elements, as described in the Address Match Lists section.

dotted-decimal

One or more integers valued 0 through 255 separated only by dots ("."), such as 123 or 45.67 or 89.123.45.67.

domain_name

A quoted string which will be used as a DNS name, for example "my.test.domain".

path_name

A quoted string which will be used as a pathname, such as "zones/master/my.test.domain".

ip_addr

An IP address in with exactly four elements in dotted-decimal notation.

ip_port

An IP port number. number is limited to 0 through 65535, with values below 1024 typically restricted to root-owned processes. In some cases an asterisk (*) can be used as a placeholder to select a random high-numbered port.

ip_prefix

An IP network specified in dotted-decimal form, followed by a slash (/) and then the number of bits in the netmask. E.g. 127/8 is the network 127.0.0.0 with netmask 255.0.0.0. 1.2.3.0/24 is network 1.2.3.0 with netmask 255.255.255.0.

key_id

A string representing the name of a shared key, to be used for transaction security.

number

A non-negative integer with an entire range limited by the range of a C language signed integer (2,147,483,647 on a machine with 32 bit integers). Its acceptable value might be further limited by the context in which it is used.

size_spec

A number, the word unlimited, or the word default.

The maximum value of size_spec is that of unsigned long integers on the machine. The unlimited option requests unlimited use, or the maximum available amount. The default option uses the limit that was in force when the server was started.

A number can optionally be followed by a scaling factor: K or k for kilobytes, M or m for megabytes, and G or g for gigabytes, which scale by 1024, 1024*1024, and 1024*1024*1024 respectively.

Integer storage overflow is currently silently ignored during conversion of scaled values, resulting in values less than intended, possibly even negative. Using unlimited is the best way to safely set a really large number.

yes_or_no

Either yes or no. The words true and false are also accepted, as are the numbers 1 and 0.