TCP handshake protocol in TCP / IP protocol, TCP protocol provides reliable connectivity services, three-way handshake to establish a connection.
The first handshake: connection is established, the client sends syn packets (syn = j) to the server, and enters SYN_SEND state, waiting for the server to confirm;
Second handshake: server receives syn packets, must confirm the customer SYN (ack = j + 1), while themselves sends a SYN packet (syn = k), i.e., SYN + ACK packet, then the server enters a state SYN_RECV;
Third handshake: the client receives the SYN + ACK packet to the server, the server sends an acknowledgment packet ACK (ack = k + 1), this packet is sent, the client and server into the ESTABLISHED state, complete the three-way handshake.
