1. A method for transferring a data packet from a source computing system to a destination computing system having a processor, said data packet having a header data portion and a user data portion, and for generating a net checksum of the user data portion of the data packet, the method comprising the steps of: receiving, at the destination computing system, the data packet from the source computing system, and transferring the data packet to a memory of the destination computing system; accumulating a gross checksum of data received at the destination computing system during the receipt of the data packet; calculating a header checksum of the header data portion of the data packet; and generating the net checksum by arithmetically subtracting the header checksum from the gross checksum.