I have enabled the PPTP server on m0n0 1.0, and I'm experiencing a problem
connecting from XP VPN clients behind a NAT/firewall over which I have no
control.

Specifically, from the VPN clients I'm able to establish a first connection,
but when it comes to the authentication (user/password), XP reports a 619
error, stating that " ... the port was disconnected ...".

My feeling is that while the vpn clients can open a connection on 1723 to
the m0n0 PPTP server, they cannot accept a second connection coming from the
PPTP server itself, since the firewall is blocking it (GRE?).

Is there any workaround for this problem?

Thank you for your time, and _thanks_ for this great m0n0 :)

Gianluca Bosco