A network interface controller includes a host interface, which is configured to be coupled to a host processor having a host memory. A network interface is configured to receive data packets from a network, each data packet including a header, which includes header fields, and a payload including data. Packet processing circuitry is configured to process one or more of the header fields and at least a part of the data and to select, responsively at least to the one or more of the header fields, a location in the host memory. The circuitry writes the data to the selected location and upon determining that the processed data satisfies a predefined criterion, asserts an interrupt on the host processor so as to cause the host processor to read the data from the selected location in the host memory.