If the software is written to listen on any particular port, then there is nothing for you to do. If your software is not working, it may be that traffic on that port is blocked by a firewall somewhere, or another process is already listening on that port.
If you are talking about the SYnergy package that allows multi-host dekstop integration, I assume you have a second computer to try accessing the port from, as a diagnostic measure. Try telneting from another computer to the computer listening to port 24800.
telnet 192.168.0.1 24800
(Substitute the actual IP of the target host).
If the connection is accepted, then the port is open with a listener. If it is refused, there is no process listening. If it times out, then there is probably a firewall intercepting the connection, and the problem becomes a firewall issue. If the connection is accepted, type 'Ctrl-]', then 'close', to close the connection gracefully.
Hope this helps.