The TCP Three-Way Handshake: The "three-way handshake" is the term for the process used to establish a connection using TCP. It is so called because it involves 3 steps, each involving the sending of one packet. These steps are as follows: Step 1. The client (the machine wishing to initiate the connection) sends a packet with the SYN flag on. Step 2. Upon receiving this packet, the host (the machine receiving the incoming connection) sends back a packet with the SYN and ACK flags on. Step 3. The client finishes the process by sending a packet with the ACK flag on. Once this is done, both sides consider the connection to be established.