Each time a recursive DNS request is made to Simple DNS Plus, it stores in memory (cache) all the different DNS records it comes across while searching for the requested records.
The cached DNS records are then used in subsequent request to locate information faster.
By default, cached DNS records are stored until they time-out based on their TTL.
Simple DNS Plus also has a "Reload DNS cache at startup" option to make its cache persistent between shutdowns and re-starts.
When this option is enabled, the currently cached records are written to disk whenever Simple DNS Plus is shut down (including when the computer is shut down correctly), and when Simple DNS Plus is later restarted, it will re-load the cache and recalculate the records' TTLs based on the time the program was closed.
Most DNS servers will not cache a DNS record for more than one week. This is also the default in Simple DNS Plus, but you can change this through the "Maximum cache time" option.
To view a snapshot of the currently cached records, from the main window click the "Cache" button or press F4.
