ok, lets clear this up a bit....
Zedric you have the right idea, BUT... those ports you mentioned best work with G6/BPFTP. If you are using ServU, you will have to open a range of ports like 1024-65535. Now before you jump up and down after seeing that range, let me explain some things as far as linksys and ftp servers (and other applications).
Ok, you need to understand what PASV mode transfer is, i am not going to explain it here, that is what google is for
. Now, port forwarding should only be used when you want a port or range open ALL THE TIME. DMZ should only be used on a pc that you use as a gateway for a hub, but nevermind that biz, back to the ftp prob.
First of all, you DONT have to PORT FOWARD any other ports other than 21 or the port that the server resides on to allow ppl to logon and get a LISTing. For this just tell your users to turn off PASV mode transfers, which is default on alot of ftp client. OR, you can tell them to use an option IP MASQ/NON Routeable IP, if that option is available. These two suggestions will allow a user to use the LIST command on a server behind a router/NAT, without having to go thru these necessary steps for PASV mode.
Now if you want the serve to work with PASV mode, you will need to do the following if you have ServU. On your browser config for linksys, go to the advanced/forwarding tab. Next, hit the port triggering button towards the bottom (this feature is only available to firmware 139 or higher i believe). When the window pops up, this is where you put your 1024 ~ 65535 range in both sets of boxes. For the Application name, just put ServUAdmin.exe, or something in reference to servU, so that in the future you know just what the heck you did this for. Also to note, make SURE you have disabled, or turned off the DMZ host, or this will confuse the router, and make it think that it is the DMZ host still, causing this not to be of any use. Also this will leave you to other vulnerabilities such as NetBios attacks, UPnP, and other vulneralbilities.
Now, for all you ppl worried about security with your linksys, you need to really read about this feature, it is not perfected by any means. This feature does NOT open this range on the router all the time, only when a request echo is sent out from an application behind the NAT to the client is recieved. If you still have worries after doing all this, just go to
www.grc.com and you will see that this range should still be stealthed or closed, unless you have forwarded other ports in the PORT FORWARDING (not the port triggering). Back to the rest of the solution....
Now that you have setup the router, it is time to setup the server to recognize a request. If using ServU 4, which i recommend for a few reasons rather than BPFTP, you need to to navigate to the SETTINGS under the DOMAINS "+". Then go to the advanced tab. Here you will see something that says "allow passive mode data transfers, use this ip". Put a check in the box, and then type in your modem's ip (not your router assigned IP). If your ISP is DHCP and you are not sure of your modem's IP (not your router assigned IP), then go to
www.dslreports.com/whois and find out your IP address.
This solution should clear up your problem, and still leave your pc "protected". Reply and let me know if you found this useful. All complaints and b*tching welcomed.