A method and system is disclosed for passing data processed by a DMA controller through a transmission filter. The method includes the DMA controller accessing data for transfer between an origination location in the system and a destination location in the system. The accessed data is passed through the DMA controller before being sent to the destination location. While the data is being passed through the DMA controller, it is passed through a transmission filter for processing. This processing may include the addition or removal of transmission protocol headers and footers, and determination of the destination of the data. This processing may also include hash-based packet classification and checksum generation and checking. Upon completion of the processing, the data is sent directly to a prescribed destination location, typically either a memory circuit or an I/O device.