Options dialog - DNS - Local Zones - Data Files
(Main window -> Options button -> DNS / Local Zones / Data Files section)

Simple DNS Plus v. 5.2
Copyright © 1999-2011 JH Software ApS
Location of DNS data files (zone files)
Specify the directory where data files are stored.
The default is the "ZoneFiles" directory under the Simple DNS Plus data directory:
Windows Vista/2008 and later: C:\ProgramData\JH Software\Simple DNS Plus
Earlier Windows versions: C:\Documents and Settings\All Users\Application Data\JH Software\Simple DNS Plus

 

Defer loading individual zones until first request (load on demand)
In setups with many zones this can greatly improve the server startup time.
Inactive zones will never be loaded, which may also improve memory usage.

 

When loading zones from disk, limit DNS record TTL (Time To Live) values
Replace lower/higher DNS record TTL values when loading DNS zones.
Can be used when you want to enforce a min/max TTL value - for example when using zone files that someone else has supplied.