18. SYN, SYN-ACK, ACK Handshake

The TCP three-way handshake is the process used to establish a TCP connection between a client and a server.

First, the client sends a SYN packet to the server, usually to a port such as 80 or 443, to request a connection.

Second, the server responds with a SYN-ACK packet. This acknowledges the client’s request and signals that the server is ready.

Third, the client sends an ACK packet back to the server. After this, the basic TCP connection is established.

Once the connection is set up, the client and server can continue with further communication, including secure communication setup if needed.

Main Idea
The TCP three-way handshake creates a connection by exchanging SYN, SYN-ACK, and ACK packets between the client and server.