In a sock stress DoS, the final ACK packet in the three-way handshake includes a window value of 0. Vulnerable services will not transmit any data in response to the connection because of the indication of any empty window on the part of the connecting client. Instead, the server will hold the data to be transmitted in memory. Flooding a server with these connections will deplete the resources of the server to include the memory, swap space, and processing power.