Telnet uses port 23. Is port 23 set on the local & remote machine? or just on the local machine?

Question

what does remote machine do with that port?

what does local machine do with that port?

Answer 1

Client (the computer connecting to the telnet server on another computer) can use any port for the outgoing connection attempt.

Server (the computer being connected to) will listen on port 23 (or whatever else has been setup) for Telnet requests from the client.

So in short the client will use whatever it wants and send the request to the port on the remote computer that the user specifies. Telnet defaults to 23 unless you tell it to try a different port.