Novell LINUX ENTERPRISE SERVER 10 SP2 - INSTALLATION AND ADMINISTRATION Installation Manual page 652

• The name of the domain to administer is world.cosmos in the first position.
• 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.
634 Installation and Administration
This ends with a ., because otherwise the zone would be appended a second time.
Alternatively, @ can be entered here, in which case the zone would be extracted
from the corresponding entry in /etc/named.conf.
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.