An HTTP server indicates its readiness to receive HTTP requests by “listening” on a port. By convention, port 80 is used for the HTTP protocol. Other Internet protocols use different ports; the port numbers between 1 and 49151 are reserved for use by standard protocols. On many operating systems, ports up to 1000 require special privileges. On your Netduino Plus, there are no such restrictions.
The use of ports in this way is merely a convention. Nothing prevents you from using one of the reserved ports for your own server programs, as long as no other program is already listening on that port. I often use port 8080 during development, which also works on a PC.
If you have used