Installing and Administering Internet Services

110 Chapter3
Configuring and Administering the BIND Name Service
Configuring a Primary Master Name Server
name The name of the subdomain. In data files, @ represents
the current origin. The current origin is the domain
configured in this file, according to the boot file. The
boot file says that the 0.0.127.in-addr.arpa domain
is configured in the db.127.0.0 file. Therefore, every
instance of @ in the db.127.0.0 file represents
0.0.127.in-addr.arpa.
The current origin is also appended to names that do
not end with a dot. For example, the 1 in the PTR line
would be interpreted as 1.0.0.127.in-addr.arpa.
class The optional class field specifies the protocol group.
IN, for internet addresses, is the most common class.
type The SOA (start-of-authority) 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
1.0.0.127.in-addr.arpa. (The current origin is
appended to the 1 in the name field, because it does not
end with a dot.)
data The SOA 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:
Serial The version number of this file,
incremented whenever the data is
changed.
Refresh Indicates (in seconds) how often a
secondary name server should try to
update its data from a master server.
Retry Indicates (in seconds) how often a
secondary server should retry after
an attempted refresh fails.