OK, I am using a Buffalo Linkstation network HDD which has a built in FTP server.
I have set the FTP server up and can access it from a local address. However, I cannot access it from another computer on the internet (i.e., outside of my LAN).
I have set my router up to forward traffic on ftp port 20 and 21 to address 192.168.0.253 (which is the Linkstation on my LAN). If I connect from outside, my Netgear router (DG834G) logs the connection attempt as "FTP Rule Match". However, all I get is a box saying, "Windows cannot access this folder. Make sure you typed the file name correctly and that you have permission to access the folder."
I have had this working in the past and I don't know what to do!