Definition - What does Three-Way Handshake mean?
A three-way handshake is a method used in a TCP/IP network to create a connection between a local host/client and server. It is a three-step method that requires both the client and server to exchange SYN and ACK (acknowledgment) packets before actual data communication begins.
A three-way handshake is also known as a TCP handshake.
Techopedia explains Three-Way Handshake
A three-way handshake is primarily used to create a TCP socket connection. It works when:
- A client node sends a SYN data packet over an IP network to a server on the same or an external network. The objective of this packet is to ask/infer if the server is open for new connections.
- The target server must have open ports that can accept and initiate new connections. When the server receives the SYN packet from the client node, it responds and returns a confirmation receipt – the ACK packet or SYN/ACK packet.
- The client node receives the SYN/ACK from the server and responds with an ACK packet.
Upon completion of this process, the connection is created and the host and server can communicate.