[pptp-server] can I have a pptp vpn between two nat's?

[Lillian Kulhanek]

Here's the setup:
  
Lan1 (Win98SE clients) is masqueraded behind a linux
gateway.  The linux pptp server is behind the gateway,
with port forwarding occurring from the gateway to
pptp server.  (vpn masquerading)

Lan2 (Wind98SE & NT4Server) is nat'ed behind a cisco
1600.  The NT server has a public address as well (2
nics).  The NT server was set up as a pptp server as
well, for the sake of testing.

The goal is for lan2 clients to log on to and access
lan1.

Here's what we can do:

1)  Home users can connect to Lan1 with pptp.
Proves that the pptp server is working.

2)  From a pc with a private address in lan1, I can
connect to the pptp server in lan2, using its public
address.  
Proves that there is no port/protocol blockage, at
least in that direction.

A pc in lan2 CANNOT make a pptp connection to the pc
in lan1.  I was wondering if this was because of
nat'ing on both sides?  But isn't portforwarding
supposed to take care of this?

I don't remember reading anything that says I can't do
this.  Can anyone enlighten me on why or why not? 
Would this also explain why I can't run NetMeeting
between the two lan's?  Although, I can't see a reason
why this should not work.  Could this be a routing
issue on the cisco box (to which the isp limits
access)?

Answers, pointers to url's, greatly appreciated.  A
timely response would also be appreciated, since I'm
at lan2 flying back to lan1 in a few days.  

Thanks,
Lillian

PS  Finally, am I missing something obvious, even an
obvious alternate solution?




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