What I have done is to alias another private ip (which is in the same subnet with the 
NT clients) to the NT domain controller. And it works. 
I typed "netstat" command at my NT dc I found there were connections to the private 
ip subnet. I believe the NT dc was using the ip address in the netbios header (which 
was not altered by the ipf/ipnat) instead of the ip header. 
I believe the NBFW should work as a proxy program for all the netbios packets but it 
takes time for me to setup the SAMBA and make the NBFW working. I noticed that the 
NBFW is programmed for Linux system? is it working on BSD system too? 
And, the current version of samba is 2.2.2. I am not too sure whether the current 
version of NBFW supports samba 2.2.2 or not (i thought it said version samba-2.2.1a-
nbfw-0.40)
Thanks.

On 8 Jan 2002 at 22:34, Steve Shockley wrote:

> > The default method for NT 4 clients is to use broadcast packets
> 
> He mentioned in an earlier post that DHCP sets his clients to use
> P-node, which is point-to-point with no broadcast.  (I personally
> usually use H-node, but that's neither here nor there.)
> 
> Try using nbtstat -a hostname or nbtstat -A <ip.address> and see if it
> can connect.
> 
> http://sourceforge.net/projects/nbfw/ may be helpful.  If nothing else
> works, an outbound pptp connection may solve your problem.