A system for protocol processing in a computer network has an intelligent network interface card (INIC) or communication processing device (CPD) associated with a host computer. The INIC or CPD provides a fast-path that avoids host protocol processing for most large multipacket messages, greatly accelerating data communication. The INIC or CPD also assists the host for those message packets that are chosen for processing by host software layers. A communication control block (CCB) for a message is defined that allows DMA controllers of the INIC to move data, free of headers, directly to or from a destination or source in the host. The CCB can be passed back to the host for message processing by the host. The INIC or CPD contains hardware circuits configured for protocol processing that can perform that specific task faster than the host CPU. One embodiment includes a processor providing transmit, receive and management processing, with full duplex communication for four fast Ethernet nodes.