My terminal emulator program telnets to 192.168.1.120:8 to send commands to an instrument, and it sends replies back that show up in the terminal window.
I think the instrument responds to these replies because they are in packets addressed to 192.168.1.120 and it knows packets that specify port 8 contain ASCII for commands to be followed. Right?
But when my computer sees packets addressed to 192.168.1.100, its own address, how does it know to write the corresponding letters in the terminal window? Is the instrument sending them to a specific port, perhaps port 23 for telnet?
The instrument happens to have its own web server with configuration pages, and I happen to have one of those open in IE while this is going on, and of course the instrument is sending some packets for this purpose too. Do they control the web page display because they are sent to port 80?
Even more complicated - my computer also has other IE windows open at the time. Supposing that they are filled with content that came in to 192.168.1.100:80, how does the content wind up in the correct IE window?
Mostly I am just curious about this -