Make a FTP Server visible over the internet?

It's simple really I did it be4 a while ago with winxp. However windows has nothing to do with ftping. Your FTP program must have a port number. You then go to your router or switch and put that FTP port number save it and boot the router. The router then hundles all requests and forward it to the connected computer which your FTP program is sitting on. Now on the Internet if you type your internet service providers ip plus the ip of your computer and port, your web browser will automatically show your FTP files. The FTP program just make it look good and easy. Otherwise the end user doesn't need your FTP program. You host they download or upload it doesnt matter.