FTP/ Firewall

[goon12]

I am running a 3com SuperStack Firewall, that site behind a Netopia(<-doing the NAT)router. Everything is working fine ( ie, ssh, ssh2, sftp2, http, https, pop3, imap, smtp, etc ). I am trying to set up a simple ftp server.

I am able to ftp into the server fine, as long as on the LAN, and using the internal IP. How ever, when I try to ftp in using the servers "real" IP address, I am able to login. When I try to "ls" the directory I get this

ftp> ls
200 PORT command successful.
425 Can't build data connection: Connection refused

I have tried using several different clients and all have the same result.

I have tried changing the mode from Passive to Active, and have the same results. I dont beleive that would have anything to do with it, because I am able to ftp fine on the LAN.

Any help would be appreciated...


Thanks,
-goon12

[cowanrl]

FTP requires 2 TCP ports to work. Port 21 to connect and port 20 to transfer data. Check to be sure your firewall device and the router are both letting through ports 20 and 21.
Since you can connect but can't transfer any data, I'd say one of them is blocking port 20.