HP-UX IP Address and Client Management Administrator's Guide (October 2009)

class The optional class field specifies the protocol group. The protocol group IN, for
Internet addresses, is the most common class. If you do not specify this field, the class
defaults to the last class specified. All the entries in the example db.cache file are of
class IN.
type Records of type NS list the name servers. The first field in an NS record is the domain
for which the name server has authority. The last field in an NS record is the fully
qualified name of the name server.
For records of type A list, the first field in an A record is the name of the name server.
The last field in an A record is the Internet address of the name server.
data The data field for an NS record provides the fully qualified name of a name server.
The data field for an A record specifies an Internet address of the name server.
The db.127.0.0 File
Each name server must have an /etc/named.data/db.127.0.0 file. Hosts running Berkeley
networking use 127.0.0.1 as the address of the loopback interface. Because the network number
127.0.0 is not assigned to any site but is used by all hosts running Berkeley networking, you must
configure each name server as authoritative for the network 127.0.0. The file
/etc/named.data/db.127.0.0 contains the resource record that maps 127.0.0.1 to the name
of the loopback address, usually localhost. The hosts_to_named program creates the
/etc/named.data/db.127.0.0 file.
The following is an example db.127.0.0 file:
;name class type data
$TTL 86400
@ IN SOA rabbit.div.inc.com root.moon.div.inc.com (
1 ; Serial
10800 ; Refresh every 3 hours
3600 ; Refresh every hour
604800 ; Expires after a week
86400 ) ; Minimum ttl of 1 day
IN NS rabbit.div.inc.com
1 IN PTR localhost
The following explains the fields in the db.127.0.0 file:
name This field specifies the name of the subdomain. In the SOA record, the at sign (@)
represents the domain name when the domain name and the origin are the same. In
the expanded notation, @ represents 0.0.127.in-addr.arpa. Similarly, for the PTR
record, 1 represents 1.0.0.127.in-addr.arpa. in the expanded notation.
class The optional class field specifies the protocol group. IN, for Internet addresses, is the
most common class.
type The start of authority (SOA) record designates the start of a domain and indicates that
this server is authoritative for the data in the domain.
The NS record designates a name server for the current origin
(0.0.127.in-addr.arpa).
PTR records are usually used to associate an address in the in-addr.arpa domain
with the canonical name of a host. The PTR record in the example db.127.0.0 file
associates the name localhost with the address 1, that is,
1.0.0.127.in-addr.arpa. (The current origin 0.0.127.in-addr.arpa is
appended to the 1 in the name field because it does not end with a dot.)
data For an SOA record, data includes the name of the host this data file was created on,
the mailing address of the person responsible for the name server, and the following
values:
72 Configuring and Administering the BIND Name Service