I've setup Remote Windows 2003 VPN Server and my gateway (shorewall NAT/firewalled) is linux box. The problem is my internal LAN cannot initiate VPN connections to Win2003 VPN Server. I can dial but when I reached verifying username and password it stops, I think there are ports to be open in my firewall. Experts your answers are all welcome.
WinXP VPN Client --> Linux BOX (shorewall NAT/firewalled) --> Win2003VPNServer