Abstract: A configuration tracking system for a call detail record (CDR) filtering system keeps track of the contexts under which CDRs are collected and filtered. The configuration tracking system is useful in a multiple concurrent filtering paradigm, in which several CDR filters may be active at any given time and the filter criteria are dynamically altered. Filter criteria for multiple filters are recorded in a dynamically changing table. The configuration tracking system maintains a historical record of the filter criteria in the dynamically changing table. The configuration tracking system updates its historical record by detecting changes in the dynamically changing filter table, comparing earlier and later versions of the table, and opening and/or closing timestamped filter records in response.