Configuring BIND

Configuring BIND server requires editing a few files. Links for those files have to be specified in the configuration file named.conf. A complete set of files is as follows:

configuration file

Defines the general aspects of the work named and specifies the source of the DNS database, which this server uses. As sources can be local files and remote servers. By default configuration file is called named.conf.

Command structure of the named.conf is similar to the C language programs. Operator ends with a semicolon (;), constants are quoted (“”),and related items are grouped with braces ({}), comment can be limited to pairs of characters /* and */, //, or #.

The main configuration commands of named.conf shows in table 1.

 

Table 1 – configuration commands of named.conf

command	function
acl	assigns Access Control List, containing IP-addresses
include	used to load an external file, that contains any of the configuration commands, to the local file
key	assigns an internal name used to reference an authentication method
logging	assigns message log
options	assigns global settings
server	assigns the properties of the remote server
zone	assigns zone

 

The contents of the named.conf file defines the server role: main zone server, slave zone server or caching server.

root hints file

Indicates root zone servers. Root zone file can be named named.ca, db.cashe, named.root or root.ca. In our implementation of the BIND server uses name named.root. During configuring name server this file DO NOT EDITING.

Loop file

Is used to resolve loopback address. Use file localhost.rev.

Forward zone file

Forward zone file define mapping domains to IP addresses. This file contain main information about domain zone.

Reverse zone file

Reverse zone file define mapping IP addresses to domains.

Forward and reverse zones files usually have descriptive names, allowing to understand what areas information are stored in a file.

These files have similar structure and consist of records of the same type, called the standard resource records, also known as RR-records.

RR-record has next format:

[name] [ttl] IN type data

name

owner name, i.e., the name of the node to which this resource record pertains. It could be a separate host or entire domain.

String in the name field is interpreted relative to the current domain, except the name of ending point.

ttl

specifies the time interval that the resource record may be cached before the source of the information should again be consulted. Zero values are interpreted to mean that the RR can only be used for the transaction in progress, and should not be cached. Usually this field left empty, in this case the default zone settings uses.

IN

Define that RR-record has Internet class.

Type

Specifies RR-record type. The main types of records listed in the table 2.

 

Table 2 – The main types of recources records

RR-record type	name	function
SOA	start of zone authority	Marks the beginning of the zone data and defines parameters that describe the area
NS	an authoritative name server	Specifies the domain names server.
A	a host address	Translate host name to IP-address
PTR	a domain name pointer (used in reverse DNS)	A PTR or “Pointer Record” is the “reverse lookup” record for a host.
MX	mail exchanger	Specifies point of mail delivery, defined for certain domain name.
CNAME	the canonical name for an alias	Defines an alias for the host name.
TXT	text	Stores random text strings.

 

data

Information specific to the type of RR-records. For example, Например, in the case of an address record (A) data field contains the IP-address.

Also, there are four directives in BIND that simplify the creation of a zone file or help to define the parameters of the RR-records.

- $ TTL directive sets the default time to live value for RR-records which do not contain an explicit parameter ttl.

- $ ORIGIN directive sets the current zone, ie domain name, which complemented all relative domain names. Relative is any domain name that does not end point. By default derective $ ORIGIN is set domain name specified in the operator zone.

- $ INCLUDE directive includes the contents of an external file as a fragment of the zone file.

- $ GENERATE directive is used to create a series of RR-records.