Problems with FTP behind Windows 2003 NAT

[Jim in Arizona]

We have a Win2003 server as our proxy running NAT. When attempting to FTP
into any ftp server using a command prompt (DOS FTP), it will connect but
any commands beyond that will just hang, like 'ls' or 'dir'.

I looked around for a solution and found that if you issue this command on
the NAT box that it should fix the problem:

netsh routing ip nat add ftp

I then restarted the RRAS service. I found that using windows explorer for
FTP works fine, but when using the command line FTP, it still hangs in the
same way:

C:\WINDOWS>ftp ftp.microsoft.com
Connected to ftp.microsoft.com.
220 Microsoft FTP Service
User (ftp.microsoft.comnone)): anonymous
331 Anonymous access allowed, send identity (e-mail name) as password.
Password:
230-Welcome to FTP.MICROSOFT.COM. Also visit
http://www.microsoft.com/downloads.
230 User logged in.
ftp> dir
501 Server cannot accept argument.
150 Opening ASCII mode data connection.

It hangs at 150.

(note that the MS connection above was done about a month ago. Any attempts
to connect to MS's ftp site now just results in an immediate disconnect: see
below)
C:\WINDOWS>ftp ftp.microsoft.com
Connected to ftp.microsoft.com.
Connection closed by remote host.

When logging into sun's ftp site:

220 ** Welcome to Sun Microsystems FTP site **
User (supportfiles.sun.comnone)): anonymous
331 Guest login ok, send your complete e-mail address as password.
Password:
230 Guest login ok, access restrictions apply.
ftp> dir
500 Illegal PORT Command

and once again it hangs at that point.

When trying to log into one of our local unix boxes (outside the lan)

C:\WINDOWS>ftp webA.mydomain.net
Connected to webA.mydomain.net.
220 ProFTPD 1.2.9 Server (ProFTPD) [123.123.123.22]
User (webA.mydomain.netnone)): mainadmin
331 Password required for mainadmin.
Password:
230 User mainadmin logged in.
ftp> dir
500 Illegal PORT command
425 Unable to build data connection: Connection refused
ftp>

Other programs like CuteFTP and FTPExplorer also come up with errors.
Strange that Windows Explorer works just fine huh but everything else does
not.
This problem is taking place on all workstations on the inside of our
windows NAT box.

If any of us change our default gateway to a linksys router running NAT,
these FTP errors go away.

Any Ideas?

TIA,
Jim