Does the port change when a TCP connection is accepted by a server?

Question

When a client connects to a server using TCP, a new socket is created for the TCP stream. Does the connection remain on the same port the connection was made or does it get changed to some other port?

Answer 1

The new socket is an application-level concept introduced because each established connection needs a unique file descriptor (also distinct from the listening file descriptor), which maps to, but isn't the same as, a TCP session. The session itself is identified by the combination of source and destination address and port. The source (client) port is usually chosen at random, while the destination (server) port is the listen port. No additional port is allocated.

Answer 2

I believe that the socket associated with the new descriptor returned by accept on the server will use the same port on the server side of the connection as the original socket (assuming "normal" definitions where the client initiates the connection). The new socket will have a different client port number (the remote port from the server's point of view).