said by viajerodevid
:... you do not need to forward ports 65000 - 65534. vsftpd.conf let's you specify pasv_min_port=0 and pasv_max_port=0 which tells vsftpd to use any available ports. Also, pasv_address can be set to either the WAN IP of the router or the LAN IP of the router. I'm not sure what the difference is, and I might have noticed a slight speed increase in vsftpd response time when using the WAN IP, but I'm not about to test this.
These links have the info needed to set up a fully-functional FTP server behind a LinkSys router.