Novell LINUX ENTERPRISE SERVER 10 - INSTALLATION AND ADMINISTRATION 11-05-2007 Installation Manual page 646

• After IN SOA is the name of the name server in charge as master for this zone.
• An e-mail address of the person in charge of this name server follows. Because
• The ( includes all lines up to ) into the SOA record.
Line 3:
The serial number is an arbitrary number that is increased each time this file
is changed. It is needed to inform the secondary name servers (slave servers) of
changes. For this, a 10 digit number of the date and run number, written as
YYYYMMDDNN, has become the customary format.
Line 4:
The refresh rate specifies the time interval at which the secondary name
servers verify the zone serial number. In this case, one day.
Line 5:
The retry rate specifies the time interval at which a secondary name server,
in case of error, attempts to contact the primary server again. Here, two hours.
Line 6:
The expiration time specifies the time frame after which a secondary name
server discards the cached data if it has not regained contact to the primary server.
Here, it is a week.
Line 7:
The last entry in the SOA record specifies the negative caching TTL—the
time for which results of unresolved DNS queries from other servers may be cached.
Line 9:
The IN NS specifies the name server responsible for this domain. gateway is
extended to gateway.world.cosmos because it does not end with a .. There
can be several lines like this—one for the primary and one for each secondary name
server. If notify is not set to no in /etc/named.conf, all the name servers
listed here are informed of the changes made to the zone data.
628 Installation and Administration
The name is expanded from gateway to gateway.world.cosmos, because
it does not end with a ..
the @ sign already has a special meaning, . is entered here instead. For
root@world.cosmos the entry must read root.world.cosmos.. The .
must be included at the end to prevent the zone from being added.