W2K3 NAT/FTP problem

[Perry Diels]

Hello,

I have setup Windows 2003 Server with RRAS VPN, NAT and IIS 6 as FTP server.
The whole system is running fine with just one problem which I cannot solve.
I'm looking to find the solution for several weeks now. The problem is that
external clients that are themselves behind a NAT on their side cannot use
our FTP server. The weird thing is that every PC with a direct Internet
connection can connect to our FTP server without any problem, PORT or
PASSIVE mode doesn't matter. This means that from our server side it *should
be* OK, for FTP the two connections (control and data) are being
established. What is the difference for a PC which is connecting from behind
a NAT (or router)? How can we solve that problem?

Some more info:

PORT mode and PASSIVE mode have been tried, both without success (from
behind a NAT on client side)
Our FTP server runs on port 1994 (I have noticed port 1993 is being used as
data connection)
Clients from behind a NAT seem to be able to establish the control
connection, but no data connection, hence there's no directory listing or
whatever.

All help appreciated.
Perry

 

[ndennen]

same problem

Hello All,

I am having the exact same problem except that I am using port 21. Everything else about NAT is working fine. Anyone locally (inside the router) can access the ftp server just fine. However, everyone outside of the NAT cannot access the data (cannot retrieve direcrotry listings or any other files). Please help!

Nate