A mechanism is provided for partial offload of connection tracking from a host processor to a network interface device. Software running in the host processor is used for connection establishment. After a connection has been established the software initializes and transfers flow-control to the network interface device. Thereafter, the network interface device continues transferring packets to the destination, while the software in the host processor monitors the flow. If the connection has been terminated or has expired flow control reverts to the software. Modes of operation are provided for network interface devices with and without a specific connection-tracking module.