|  |  | The SYN flood attack can block a single service on one host by sending only 10 to 15 packets every couple of minutes. This attack takes advantage of the three-step handshake of TCP/IP. The hacker sends the first step of the handshake. The victim stores information in that port's queue, sends the second step, and then waits for the third step, which never comes. The queue fills (6 to 10 packets in length) and the system will no longer accept any incoming connection requests until the entries in the queue time-out (75-100 seconds). In this attack, there are no other negative effects on the system or the network.