TCP protocol three times handshake process

Common front-end interview questions TCP Protocol three handshake process

1. The first 1 The second handshake Establishing a connection

The message sent by the client to the server SYN Package information SYN Code for 1

2. The first 2 The second handshake The server responded to the client , Used to accept and connect requests

The message returned by the server to the client SYN Code and ACK All codes are 1, Also called syn-ack Message information .

3. The first 3 The second handshake The client finally sends it to the server , Used to confirm the server reply .

The message information finally sent by the client to the server ACK Code for 1, We call it ack package .

4. The first 4 Time It's also known as Finally disconnect .

summary

1 The second handshake ： The client sends with syn The symbol of code connects to the packet server .
2 The second handshake ： Server return syn+ack Connection request for flag + Reply data to the client .
3 The second handshake ： The client finally sends ack Flag data to the server . Establishing a connection , It's ready to transfer data .