The incoming connection port.[...]
You can choose from which port bitlet should try to bind the incoming connection socket.BitLet tries to find an available port incrementally from the port you set.If the led indicator never gets green you are probabily behind NAT, please forward the ports on your public router to the same ports on your NATted host.
If you have an UPnP enabled gateway bitlet will try to automatically forward the correct port.
Note that this will affect only the new downloads.
Maximum upload rate
The maximum upload rate in Kilobytes.[...]
Many users still have ADSL connection: in order to get a higher download rate they could try to limit their upload bandwidth.