Data centers availability is mandatory and is conditioned by a quick response to failures and attacks thanks to efficient live forensics. However, this task is lately impossible to complete with classic systems because of encountered data rates and service diversity. Moreover, Software-Defined Networking (SDN) devices agility requirements prevent the use of Application Specific Integrated Circuits (ASIC) solutions due to long development time. New solutions of smart Network Interface Cards (NIC) with embedded Field Programmable Gate Arrays (FPGA) are considered, as in Microsoft Azure solution. FPGAs ensure high throughput processings without packet loss to offload CPU processing, but their configurations support only sparse firmware upgrades and shut down processings. This paper proposes an hybrid architecture to realize agile high performance traffic forensics. This work combines hardware performance, high throughput, and software high flexibility to achieve data rates beyond 40 Gb/s while being configurable at runtime through parameters. A software API allows a user-friendly configuration without stopping processings. The implementation of a flexible packet parser, first block of the packet processing chain, demonstrates the viability of the concept.