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

The /etc/named.conf file denotes that the div.inc.com domain is configured in
the db.div file. Therefore, every instance of @ in the db.div file represents
div.inc.com.
The SOA record specifies the name of the host this data file was created on, an electronic
mail address of the name server’s technical contact, and the following values:
Serial
Indicates the version number of this file, incremented whenever the
data is changed.
Refresh
Indicates (in seconds) how often a slave name server must try to
update its data from a master server.
Retry
Indicates (in seconds) how often a slave server must retry after an
attempted refresh fails.
Expire
Indicates (in seconds) how long the slave name server can use the
data before it expires for lack of a refresh.
Minimum ttl
Indicates (in seconds) the minimum number of seconds the name
server is allowed to cache data. After the ttl (time to live) value
expires, the name server must discard the cached data and obtain
new data from the authoritative name servers
NS Name Server records. The NS records provide the names of the name servers and the
domains for which the domain has authority. The domain for the name servers in the
example db.div file is the current origin (div.inc.com), because @ was the last
domain specified.
A Address records. A records provide 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 host name. When a
name server looks up a name and finds a CNAME record, it replaces the name with the
canonical name and looks up the new name. All other resource records must use the
canonical name instead of the actual host name.
WKS Well Known Service records. The WKS record describes the services provided by a
particular protocol on a particular interface. The protocol is any of the entries in the
/etc/protocols file. The list of services is as specified in the host’s /etc/services
file. You can specify only one WKS record per protocol per address.
MX Mail Exchanger records. MX records specify a 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 for the target host if the target host is down or inaccessible. The preference
field specifies the order a mailer must follow if there is more than one mail exchanger
for a given host. A low preference value indicates a higher precedence for the mail
exchanger.
In the example db.div file, mail for rabbit must go to rabbit.div.inc.com first.
If rabbit is down, its mail must be sent to the host indigo.div.inc.com.
See HP-UX Mailing Services Administrator’s Guide for information on Sendmail and
how Sendmail uses the name server’s MX records for routing mail.
$TTL Indicates (in seconds) the time to live value for records that do not have the ttl value
defined in the data field.
74 Configuring and Administering the BIND Name Service