UCS 2.4 - Univention

4 Univention Directory Manager
100
There are two commonly used patterns for this serial number:
• Start with 1 and increment the serial number with each change.
• By including the date the number can be entered in the format YYYYMMDDNN, where Y stands
for year, M for month, D for day and N for the number of the change of this day.
If the serial number is not changed manually, Univention Directory Manager automatically increases
the value by 1 if [OK] was clicked. If the process is cancelled, the serial number remains unchanged.
Refresh interval (*)
The time span after which the slave name server checks that its copy of the zone data is up-to-date.
Common values are between one and 24 hours. The preset value is eight hours.
Retry interval (*)
The time span after which the slave name server tries again to check that its copy of the zone data
is up-to-date after a failed attempt to update. This time span is usually set to be less than the update
interval, but can also be equal. The preset value is two hours.
Expiry interval (*)
The time span after which the copy of the zone data on the slave becomes invalid if it could not be
checked to be up-to-date.
For example, an expiry interval of one week means that the copy of the zone data becomes invalid
when all requests to update in one week fail. In this case, it is assumed that the files are too outdated
after the expiry interval date to be used further. The slave name server can then no longer answer
name resolution requests for this zone.
Common periods for this are one week. Longer expiry intervals can be selected if there are problems
with the network connections to the master name server. The preset value is one week.
Minimum Time-to-Live (*)
The minimum time to live specifies how long other servers can cache no-such-domain (NXDOMAIN)
answers. This value cannot be set at more than 3 hours, the preset value is 3 hours.
’Name servers’ tab
Name servers (usually called NS records in DNS terminology) can be assigned to a zone on the
Name servers tab. The name server entered on the Start of Authority tab appears automatically in
the Entries list field.
Name servers (*)
The fully qualified domain name with a full stop at the end of the relative domain name of the name