Firewall/NAT

I have an ftp server running on a windows 2003 server and IIS6. When ever I try using a passive ftp connection (web browser, CuteFTP or FileZilla) the connection will drop after the user authenticates. I have tried this from a few systems and different locations with the same result.

For testing purposes the m0n0wall is setup to allow me full access on all ports to help eliminate a port blocking issue. 

All I can find is that the server is returning the internal IP back to the client and not the external NAT address. Is this normal and if so are there settings I need to be looking for?

Thanks

I've always run a 3rd party ftp server so I'm not exactly sure how this would be accomplished w/ the Microsoft server, but typically you have to manually configure the ftp server and the firewall to play nice with PASV.  In Serv-U (probably not the best server, its just what I use) you can manually tell the server what your WAN IP is, as well as set up the ports you want the server to listen on for PASV.  Once you've told the server which ports to use for PASV you'll need to forward those to your server.  Simply enabling all ports/protocols in the firewall isn't going to be enough.

I have the same problem but with Linux ftp server whet 1:1 nat is enabled (ftp server is on WAN side , ftp client is on LAN side). Ftp client it is Total Commander. Prolem is wiht passive and with active mode. I testing connection on linux based firewall with 1:1 NAT and connection among ftp client and server is OK without any problems.

Does the following link answer your query?:
http://wiki.m0n0.ch/wikka.php?wakka=PassiveFTP