Enabling Dst With The Tz Database - D-Link NetDefendOS User Manual

Introduction
Many regions follow Daylight Saving Time (DST) (or "Summer-time" as it is called in some
countries) and this means clocks are advanced for the summer period. The principles regulating
DST vary from country to country, and in some cases there can be variations within the same
country. For this reason, NetDefendOS cannot automatically know how to adjust for DST without
some input from the administrator. Adjusting for DST in NetDefendOS can be done in one of the
following ways:
• Specifying a Location Name for tz Database Lookup
NetDefendOS has a local copy of the tz database which is used to map a location name to the
daylight saving rules for that location. The administrator just has to specify the correct
location name so NetDefendOS can perform a lookup in the database to find the DST rules to
apply.
Note that the tz database is also known as the Olson database or the IANA time zone database
or even just tzdata. In this document it will be referred to as the tz database.
• Specifying the DST Offset Manually
This option allows the administrator to specify the DST rule manually by entering an offset
from the time in the specified timezone along with a start and end day for the offset to be
applied.
These options are described next.
Specifying a Location Name for tz Database Lookup
The tz database is a publicly available database for mapping a location name to the daylight
saving rule for a given location. The database is part of the NetDefendOS distribution and is
stored locally.
The location string for database lookup is specified as a hierarchical set of locations. The
following are some examples of location string values.
• America/Costa_Rica
• Asia/Sakhalin
• Antarctica/DumontDUrville
• Europe/Stockholm
To set the correct daylight saving rules, the administrator must assign the relevant location string
value to the Location property of the NetDefendOS DateTime object. The exact string name is not
needed beforehand because the NetDefendOS Web Interface will provide the complete location
list for selection and the CLI will provide the complete list with tab completion.
Example 2.21. Enabling DST with the tz Database
This example shows how the NetDefendOS system time is set for the correct daylight saving
rules for Stockholm, Sweden.
Command-Line Interface
gw-world:/> set DateTime DSTEnabled=Yes
Chapter 2: Management and Maintenance
DSTMode=Automatic
Location=Europe/Stockholm
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