Ports and Sockets
When we say an application/process wants to listen on a port, it simply calls a function in OS. This native function then adds an entry to the table which has a map of port number and pointer to a callback function of the application which must be informed when kernel receives any data on that port.
Port
It's a network property but still only logical. The network driver will open up the TCP-IP packets until layer 4 to see the destination IP and port.
Server Socket
This is the actual object which basically lets the server application to hook into the port. Here socket can be considered as the electrical socket where any appliance must connect if it needs to get power.
When kernel sees data for a specific thread, it then schedules the thread that was put to sleep for a specific file descriptor. The application will continue executing which means, it will accept this and return a socket object.
This is an infinite loop which will be polling/waiting for new connections.
This socket will be used by the entire network session to transfer data between source and destination. The same socket can be used by multiple messages,
Socket
This is the actual object that's used by the application to read and send data back.
The acceptor thread then hands over the task to worker thread to process the data coming from socket.
Port is just logical.
Socket is just an C object which is used to read data from buffer and also write response back to buffer.
Port is a network property. It's important to understand that it's only virtual. Operation system simply binds the requested port to the process. It's the responsibility of the port to accept connections whenever the kernel's network stack sees that there is a packet for a specific port.
Where as socket is how a network connection is expressed in software. Best explanation - UNIX socket is (in code) a data structure (or object) that you can use to send or receive data. This object has two queue fields. One for incoming data and one for outgoing data.