1. A computer system for facilitating a post-event reconstruction and analysis of a security breach or other catastrophic event on a computer network, the system comprising: network interface circuitry configured to passively and continuously monitor the network at a network connection point to generate a packet stream, the packet stream comprising raw data packets that are transmitted on the network by other computer systems of the network; at least one computer processor configured to process the packet stream to generate an archival data stream; and a data recording unit operatively coupled to the processor, the recording unit configured to record the archival data stream onto a non-volatile storage medium to generate a low-level archival recording of network traffic.