Tired of trying to find a non malwere program to port forward minecraft via automatically. Look no more. The port is configurable on which port to port forward in the launch.bat file. Make sure UPNP and port forwarding are both on.
The embedded library is from https://github.com/adolfintel/WaifUPnP and is under GNU Lesser General Public license
I comply with the rule and have an open source fork: https://github.com/jredfox/WaifUPnP
Since this isn't a minecraft mod on minecraft close the port will not close this you can either use lan-essentials or run the close port bat file