Error 789 - L2TP / IPSec

[netsec1]

I have Windows Vista and XP SP3 system which am trying to configure configuring L2TP/IPsec client connecting to Check Point Gateway. After lots of research I finally managed to do it successfully using VMWARE but in real environment - it is not working. The only difference that i can think of is NAT - since in VMware client and gateway were on same network. Debugging on the gateway shows this:

Gateway <-- Client (Phase1 Packet1)
Gateway --> Client (Phase1 Packet2)

After which there is no further traffic recieved by the gateway. I searched and found this KB http://support.microsoft.com/default.aspx?kbid=885407 which says to set it to 1 and 2. I did the same but still did not work.

Does anyone here have knowledge regarding this? Please help me out. Thank you.

[Carley]

To resolve this problem, you are able to make use of a preshared key on both ends of the VPN connection. The role of implementations supports L2TP/IPSec gateway to gateway VPN with a preshared key used for Internet Key Exchange (IKE) authentication. I hope this will help you to clear your some doubt. If you are not still confused then search it on Google I am sure that you will get appropriate solution on different websites. Thank you.