Configuring and Managing MPE/iX Internet Services (MPE/iX 6.5)

128 Chapter8
DNS BIND/iX
Data Files
The open parenthesis at the end of the line allows you to split the SOA
record across physical lines for readability:
9602171 ; Serial
36000 ; Refresh every 10 hours
3600 ; Retry after 1 hour
360000 ; Expire after 100 hours
36000 ; Minimum TTL is 10 hours )
The “serial” field was discussed earlier.
The remaining four fields specify various time intervals (all values in
seconds) used by the secondary name server:
Refresh The time interval that must elapse between each poll of
the primary by the secondary name server (here 36,000
seconds or 10 hours). If the “serial number” has been
updated on the primary, the secondary assumes its data
is stale and requests updated information as a “zone
transfer.”
Retry The time interval used between successive connection
attempts by the secondary to reach the primary name
server in case the first attempt failed (here 3,600
seconds or one hour). Generally, less than the “refresh”
time.
Expire The time interval after which the secondary expires its
data if it can’t reach the primary name server (here
360,000 seconds or 100 hours). The secondary will
refuse to service requests after this interval.
Minimum The minimum time-to-live value, which specifies how
long other servers should cache data from the name
server (here 36,000 seconds or 10 hours).
There are several types of resource records, identified by the key word
in field three of each record. You may present records in any order, but
try to organize them for clarity. The NS (name server) record tells the
hosts that query your server where the name servers for this domain
can be found:
maxx.net. IN NS nova.maxx.net.
You must include in this list at least one name server, that is the name
of the server specified in the SOA record. You can list multiple name
servers for your domain. In fact, your domain should have at least two
name servers. Your Internet service provider will probably allow you to
use their name server as a secondary for your domain, but it must have
the trailing dots!
maxx.net IN A 204.251.17.241
The first A record, which resolves a fully-qualified host name to an IP
address, is a special one. It defines an IP address for unqualified