1. A packet filtering method comprising: filtering packets received via a network interface card coupled to a host employing an instruction set associated with a pseudo-machine, wherein the instruction set is generic, and a set of instructions of the instruction set implements at least one filter rule, the filtering comprising: obtaining a packet of the received packets for filtering; and processing bytes of the packet as a bytestream and applying the at least one filter rule to the bytestream to filter the packet, wherein filtering the packet comprises one of accepting the packet, accepting the packet with modification, or discarding the packet, and wherein the applying is performed in any one of a plurality of locations without customization of the generic instruction set.