You can control how many days of data are retained in the configuration class. The value is set by changing the value of Configuration.Cashing.BufferFirewallData
Requirements
Target Platforms: Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2