| Description | string | This defines whether the FilterList is used for input, output, or both input and output filtering. All values are used with respect to the interface for which the FilterList applies.
"Not Applicable" (0) is used when there is no direction applicable to the FilterList. "Input" (1) is used when the FilterList applies to packets that are inbound on the related interface. "Output" (2) is used when the FilterList applies to packets that are outbound on the related interface. "Both" (3) is used to indicate that the direction is immaterial, e.g., to filter on a source subnet regardless of whether the flow is inbound or outbound. "Mirrored" (4) is also applicable to both inbound and outbound flow processing, but indicates that the filter criteria are applied asymmetrically to traffic in both directions and, thus, specifies the reversal of source and destination criteria (as opposed to the equality of these criteria as indicated by "Both"). The match conditions in the aggregated FilterEntryBase subclass instances are defined from the perspective of outbound flows and applied to inbound flows as well by reversing the source and destination criteria. So, for example, consider a FilterList with 3 FilterEntries indicating destination port = 80, and source and destination addresses of a and b, respectively. Then, for the outbound direction, the filter entries match as specified and the 'mirror' (for the inbound direction) matches on source port = 80 and source and destination addresses of b and a, respectively. |