Umm I'm still confused as to what you need.
I have a router also. MY FTP
server ran fine - but other people had to DISABLE PASSIVE MODE to connect successfully to it. Otherwise, it wouldn't provide a file listing. You don't worry about the PASSIVE/ACTIVE end of it if you're the one serving files to other people. Just tell others to disable passive mode in their FTP client when connecting to you. And don't forget to open the port on thru your router.
It's called
BPFTP server. Serv-U, I'm sure, will work also.