What is a three-way handshake process?

It’s called three-way handshake because three segments are exchanged between the server and the client.

• SYN : The client wants to establish a connection with the server, and sends a segment with SYN(Synchronize Sequence Number) to the server if the server is up and has open ports.
• SYN + ACK : The server responds to the client request with SYN-ACK signal bits set if it has open ports.
• ACK : The client acknowledges the response of a server and sends an ACK(Acknowledgment) packet back to the server.