open command prompt and type IPconfig
instead of putting in the IP you got from www.cmyip.com put in your Ipv4 address.
Run the .jar or .exe file and it should work
people not on your network have to connect with your external Ip which is the one found on cmyip.com altough anyone on your network should connect with your ipv4 address
IPV4 eg: 192.xxx.x.xxx
Extrnal ip eg: 180.xxx.x.xxx