Installing and Administering Internet Services

112 Chapter3
Configuring and Administering the BIND Name Service
Configuring a Primary Master Name Server
update its data from a master server.
Retry Indicates (in seconds) how often a
secondary server should retry after
an attempted refresh fails.
Expire Indicates (in seconds) how long the
secondary name server can use the
data before it expires for lack of a
refresh.
Minimum ttl The minimum number of seconds for
the time to live field on other resource
records for this domain.
NS Name Server records. The NS records give the names of
the name servers and the domains for which they have
authority. The domain for the name servers in the
example is the current origin (div.inc.com), because @
was the last domain specified.
A Address records. The A records give the internet
addresses for all the hosts in the domain.
The current origin is appended to names that do not
end with a dot. For example, localhost in the first A
record is interpreted as localhost.div.inc.com.
HINFO Host Information records. The HINFO records indicate
the hardware and operating system of the host.
CNAME Canonical Name record. The CNAME record specifies an
alias for a canonical name (the host’s official name). If
an alias name is looked up, it is replaced with the
canonical name and data for the canonical name is
looked up. All other resource records should use the
canonical name instead of the alias.
WKS Well Known Service records. The WKS record lists the
services supported by a host. The list of services comes
from the host’s /etc/services file. There should be
only one WKS record per protocol per address.
MX Mail Exchanger records. MX records specify a weighted
list of hosts to try when mailing to a destination on the
Internet. The MX data indicates an alternate host or list
of hosts that accept mail forthe target host if the target