File

Purpose

Defines the configuration and behavior of the named daemon.

Description

The /etc/named.conf file is the default configuration file for the named server. If the named daemon is started without specifying an alternate file, the named daemon reads this file for information on how to set up the local name server.

Note: The named daemon reads the configuration file only when the named daemon starts or when the named daemon receives an SRC refresh command or a SIGHUP signal.

The data in the named.conf file specifies general configuration characteristics for the name server, defines each zone for which the name server is responsible (its zones of authority), and provides further config information per zone, possibly including the source DOMAIN database file for the zone.

Any database files referenced in the named.conf file must be in Standard Resource Record Format. These data files can have any name and any directory path. However, for convenience in maintaining the named database, they are generally given names in the following form: /etc/named.extension. The general format of named data files is described in DOMAIN Data File, DOMAIN Reverse Data File, DOMAIN Cache File, and DOMAIN Local File. 

Format

General

Comments in the named.conf file can begin with a # (pound sign) or // (two forward slashes), or can be enclosed in the C-style comment characters, e.g., /* comment text */.

Configuration options are lines of text beginning with a keyword, possibly including some option text or a list, and ending in a ; (semicolon).

The named.conf file is organized into stanzas.  Each stanza is an enclosed set of configuration options that define either general characteristics of the daemon or a zone configuration.  Certain stanza definitions are allowed only at the top-level, therefore nesting these stanzas is not allowed.  The current top-level configuration stanza keywords are: acl, key, logging, options, server, and zone.

Further configuration information can be incorporated into the conf file via the include keyword.  This keyword directs the daemon to insert the contents of the indicated file into the current position of the include directive.

Access Control List (ACL) Definition

acl acl-name {
    access-element;
    [ access-element; ... ]
};

Defines an access control list to be referenced thoughout the configuration file byacl-name. Multiple acl definitions can exist within one configuration file provided that each acl-name is unique. Additionally, four default access control lists are defined:

• any Any host is allowed.
• none No host is allowed.
• localhost Only the localhost is allowed.
• localnets Only hosts on a network matching a name server interface is allowed.

acl hostlist1 {
    !9.53.150.239;
    9.3.149/24;
};

Key Definition

key key-name {
    algorithm alg-id;
    secret secret-string;
};

Defines an algorithm and shared secret key to be referenced in a server stanza and used for authentication by that name server. This feature is included for future use and is currently unused in the name server.

Logging Configuration

logging {

    [ channel channel-name {
       ( file file-name
             [ versions ( num-vers | unlimited ) ]
             [ size size-value ]
       | syslog ( kern | user | mail | daemon |
                  syslog | lpr | news | uucp )
       | null );
       [ print-category ( yes | no ); ]
       [ print-severity ( yes | no ); ]
       [ print-time ( yes | no ); ]
      }; ... ]
    [ category category-name {
          channel-reference;
          [ channel-reference; ... ]
      }; ... ]
};

In this newest version of the name server, the logging facility has been greatly improved to allow for much reconfiguration of the default logging mechanism. The logging stanza is used to define logging output channels and to associate the predefined logging categories with either the predefined or user-defined logging output channels.

When no logging stanza is included in the conf file, the name server still logs messages and errors just as it has in previous releases. Informational and some critical messages will be logged through the syslog daemon facility, and debug and other esoteric information will be logged to the named.run file when the global debug level (set with the -d command-line option) is non-zero.

Global Options

options {
    [ directory path-string; ]
    [ named-xfer path-string; ]
    [ dump-file path-string; ]
    [ pid-file path-string; ]
    [ statistics-file path-string; ]
    [ auth-nxdomain ( yes | no ); ]
    [ fake-iquery ( yes | no ); ]
    [ fetch-glue ( yes | no ); ]
    [ multiple-cnames ( yes | no ); ]
    [ notify ( yes | no ); ]
    [ recursion ( yes | no ); ]
    [ forward ( only | first ); ]
    [ forwarders { ipaddr; [...] }; ]
    [ check-names
       ( master|slave|response )
       ( warn|fail|ignore ); ]
    [ allow-query { access-element; [...] }; ]
    [ allow-transfer { access-element; [...] ); ]
    [ listen-on [ port port-num ] { access-element; [...] }; ... ]
    [ query-source [ address ( ipaddr|* ) ] [ port ( port|* ) ]; ]
    [ max-transfer-time-in seconds; ]
    [ transfer-format ( one-answer | many-answers ); ]
    [ transfers-in value; ]
    [ transfers-out value; ]
    [ transfers-per-ns value; ]
    [ coresize size-value; ]
    [ datasize size-value; ]
    [ files size-value; ]
    [ stacksize size-value; ]
    [ clean-interval value; ]
    [ interface-interval value; ]
    [ statistics-interval value; ]
    [ topology { access-element; [...] }; ]
};

Defines many globally available options to to modify basic characteristics of the name server.

Because some of the options in this configuration stanza may modify the behavior in how the named daemon will read and interpret later sections of the named file, it is highly recommended that the options stanza be the first stanza listed in the configuration file.

Server Specific Options

server ipaddr
{
    [ bogus ( yes | no ); ]
    [ transfers value;
]
    [ transfer-format ( one-answer |
many-answers ); ]
}

Modifies the behavior in which the remote name server matching the specified ipaddr IP address should be treated.

Zone Definition

zone domain-string [ class ] {
    type ( hint | stub | slave | master );
    [ file path-string; ]
    [ masters { ipaddr; [...] }; ]
    [ check-names ( warn | fail | ignore ); ]
    [ allow-update { access-element; [...] }; ]
    [ update-security ( unsecured | presecured | controlled ); ]
    [ allow-query { access-element; [...] }; ]
    [ allow-transfer { access-element; [...] }; ]
    [ max-transfer-time-in seconds; ]
    [ notify ( yes | no ); ]
    [ also-notify { ipaddr; [...] }; ]
    [ dont-notify { ipaddr; [...] }; ]
    [ notify-delaytime seconds; ]
    [ notify-retrytime seconds; ]
    [ notify-retrycount value; ]
    [ dump-interval seconds; ]
    [ incr-interval seconds; ]
    [ deferupdcnt value; ]
    [ key-xfer ( yes | no ); ]
    [ timesync ( yes | no ); ]
    [ timesync-xfer ( yes | no ); ]
    [ save-backups ( yes | no ); ]
    [ ixfr-directory path-string; ]
    [ separate-dynamic ( yes | no ); ]
};

The zone stanza is used to define a zone, its type, possible location of data, and operating parameters. The domain-string is a quoted string specifying the zone, where "." is used to specify the root zone. The class paramter specifies the class of the zone as either in, hs, hesiod, or chaos. By default, the class is assumed to be IN.

Examples

The following examples show the some of the various ways to use configure a simple named.conf file. In these examples, two networks are represented: abc and xyz.

Network abc consists of:

• gobi.abc, the master name server for the abc network, 192.9.201.2
• mojave.abc, a host machine, 192.9.201.6
• sandy.abc, a slave name server for the abc network and the gateway between abc and xyz, 192.9.201.3

Network xyz consists of:

• kalahari.xyz, master name server for the xyz network, 160.9.201.4
• lopnor.xyz, a host machine, 160.9.201.5
• sahara.xyz, a host machine and hint name server for the xyz network, 160.9.201.13
• sandy.xyz, a slave name server for the xyz network and gateway between abc and xyz, 160.9.201.3

  Note: Note that sandy, a gateway host, is on both networks and also serves as a slave name server for both domains.

   

1. The /etc/named.conf file for gobi.abc, the master name server for network abc, contains these entries:
   
   #
   # conf file for abc master server  - gobi.abc
   #
   server 192.9.201.3 {
       transfer-format many-answers;
   };
   
   zone "abc" in {
       type master;
       file "/etc/named.abcdata";
       allow-update { localhost; };
   };
   
   zone "201.9.192.in-addr.arpa" in {
       type master;
       file "/etc/named.abcrev";
       allow-update { localhost; };
   };
   
   zone "0.0.127.in-addr.arpa" in {
       type master;
       file "/etc/named.abclocal";
   };
   
2. The /etc/named.conf file for kalahari.xyz, the master name server for network xyz, contains these entries:
   
   #
   # conf file for abc master server  -  kalahari.xyz
   #
   acl xyz-slaves {
       160.9.201.3;
   };
   
   options {
       directory "/etc";
       allow-transfer { xyz-slaves; localhost; };
   };
   
   zone "xyz" in {
       type master;
       file "named.xyzdata";
   };
   
   zone "9.160.in-addr.arpa" in {
       type master;
       file "named.xyxrev";
   };
   
   zone "0.0.127.in-addr.arpa" in {
       type master;
       file "named.xyzlocal";
   };
   
3. The /etc/named.conf file for sandy, the slave name server for networks abc and xyz, contains the following entries:
   
   #
   # conf file for slave server for abc and xyz - sandy
   #
   options {
       directory "/etc";
   };
   
   zone "abc" in {
       type slave;
       masters { 192.9.201.2; };
       file "named.abcdata.bak";
   };
   
   zone "xyz" in {
       type slave;
       masters { 160.9.201.4; };
       file "named.xyzdata.bak";
   };
   
   zone "201.9.192.in-addr.arpa" in {
       type slave;
       masters { 192.9.201.2; };
   };
   
   zone "9.160.in-addr.arpa" in {
       type slave;
       masters { 192.9.201.4; };
   };
   
   zone "0.0.127.in-addr.arpa" in {
       type master;
       file "named.local";
   };
   
4. The /etc/named.conf file for sahara, a hint name server for the network xyz, contains the following entries:
   
   #
   # conf file for hint server for xyz - sahara
   #
   zone "." in {
       type hint;
       file "/etc/named.ca";
   };
   
   zone "0.0.127.in-addr.arpa" in {
       type master;
       file "/etc/named.local";
   };
   

Files

Related Information

The named daemon.

The syslogd daemon.

The DOMAIN cache file format, DOMAIN local file format, DOMAIN data file format, DOMAIN Reverse data file format, rc.tcpip file format.

Configuring a Primary Name Server and Naming for TCP/IP in System Management Guide: Communications and Networks.