"Network communication" server-side socket listening 80 port, to establish a connection to transmit data is also used 80 port?

1. Server-side socket monitoring 80 port, to establish a connection to transmit data is also used in the 80 port?

Answer: Yes. When the connection is established, the server assigns a new socket, but the source port number is 80. Socket is composed of protocol type, source IP, Destination IP and source port, destination port five parts, theoretically speaking, the different connected sockets as long as the five parts are not exactly the same. As long as the data is not exactly the same, the data can be distinguished by different connections.

Attached: This is also the reason that the data of the server listening port can be crawled to all the connected network packets under the service through the tcpdump and other network grasping tools.

2. Does sending and receiving data using the same port number result in reduced bandwidth utilization or blocked ports?

Answer: No. The port is just a number, not the actual physical port, so there is no port blocking problem. In the transmission of data communication network, only the network layer, link layer and physical layer are used. The port is the transport layer thing, and it doesn't matter. Therefore, the knowledge that the port number will affect bandwidth usage is wrong.

"Network communication" server-side socket listening 80 port, to establish a connection to transmit data is also used 80 port?