DOMAIN Data File Format for TCP/IP

Purpose

Stores name resolution information for the named daemon.

Description

The host's data file is one of the DOMAIN data files and contains name-to-address resolution mapping information for all machines in the name server's zone of authority. The name of the host's data file is specified in the named boot file. This file should exist only on name servers that are designated as primary for a domain. There may be more than one host's data file per primary name server.

All entries in this file must be in Standard Resource Record Format. Valid resource records in this file are:

• Start of Authority (SOA)
• Name Server (NS)
• Address (A)
• Mailbox (MB)
• Mail Exchanger (MX)
• Mail Group (MG)
• Mail Rename (MR)
• Canonical Name (CNAME)
• Well Known Services (WKS)
• Host Information (HINFO)

Except for comments (starting with a ; (semicolon) and continuing to the end of the line), the resource records in the data files generally follow the format of the resource records that the named daemon returns in response to queries from resolver routines.

Two awk scripts, addrs.awk and hosts.awk, are provided in the /usr/samples/tcpip directory to assist you in converting your existing /etc/hosts file to DOMAIN data files. The awk scripts also contain instructions for their use. Refer to these files for more information on the conversion.

Examples

The following examples show the various ways to use the DOMAIN host's data file. In these examples, two networks are represented: abc and xyz.

Network abc consists of:

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

Network xyz consists of:

• kalahari.xyz, primary 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 cache-only name server for the xyz network, 160.9.201.13
• sandy.xyz, a secondary name server for the xyz network and gateway between abc and xyz, 160.9.201.3
  Note: Host sandy, a gateway host, is on both networks and also serves as secondary name server for both.

1. The primary host data file for network abc, stored on host gobi.abc, contains the following entries:

   ;
   ;primary host data file for abc - gobi.abc
   ;
   @                 IN        SOA      gobi.abc.  root.gobi.abc.  (
                                        1.1     ;serial
                                        3600    ;refresh
                                        600     ;retry
                                        3600000;expire
                                        86400   ;minimum
                                        )
   ;name servers for abc
                     IN        NS       gobi.abc.
   ;other name servers
                     IN        NS       kalahari.xyz.
   kalahari.xyz.     IN        A        160.9.201.4
   ;
   ;define local loopback host
   localhost         IN        A        127.1
   ;
   ;define all hosts in abc
   loopback IN       CNAME     localhost.abc
   gobi              IN        A        192.9.201.2
   gobi-abc IN       CNAME     gobi.abc
   sandy             IN        A        192.9.201.3
                     IN        WKS      192.9.201.3 
   udp tftp nameserver domain
                     IN        WKS      192.9.201.3 tcp (
                                        echo telnet smtp discard uucp-path 
                                        systat daytime netstat chargen ftp 
                                        time whois finger hostnames domain
                                        )
   sandy-abc         IN        CNAME    sandy.abc
   mojave            IN        A        192.9.201.6
                     IN        HINFO    System ABC 3.1
   mojave-abc        IN        CNAME    mojave.abc.

2. The primary host data file for network xyz, stored on host kalahari.xyz, contains the following entries:

   ;
   ;primary host data file for xyz - kalahari.xyz
   ;
   @                 IN        SOA      kalahari.xyz.  root.kalahari.xyz.  (
                                        1.1     ;serial
                                        3600    ;refresh
                                        600     ;retry
                                        3600000;expire
                                        86400   ;minimum
                                        )
   ;
   ;nameservers for xyz
   ;
                     IN        NS       kalahari.xyz.
   ;
   ;other nameservers
                     IN        NS       gobi.abc.
   gobi.abc.         IN        A        192.9.201.2
   ;
   ;define local loopback host
   localhost         IN        A        127.1
   ;
   ;define all hosts in xyz
   loopback IN        CNAME    localhost.xyz.
   kalahari IN        A        160.9.201.4
   ns-xyz             IN       CNAME    kalahari.xyz.
   kalahari-xyz       IN       CNAME    kalahari.xyz.
                      IN       HINFO    System ABC 3.1
   sahara             IN       A        160.9.201.13
                      IN       WKS      160.9.201.13 ( 
                                        udp tftp nameserver domain 
                                        )
                      IN       WKS      160.9.201.13 tcp (
                                        echo telnet smtp discard uucp-path
                                        systat daytime netstat chargen ftp 
                                        time whois finger hostnames domain
                                        )
                      IN       HINFO    System ABC 3.1
   lopnor             IN       A        160.9.201.5
   lopnor-xyz         IN       CNAME    lopnor.xyz.
                      IN       HINFO    System ABC 3.1
   sandy              IN       A        160.9.201.3

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