Fortigate on AWS - What default gateway for EC2 Vm's?

[mark_brown]

Hi

Having lots of intermittent problems with Fortigate 6.4 on AWS.

All up and running but finding that some VPNs dont work with EC2 instances.     I have created the EC2 instance with the default networking and get to the outside world as the route table on the private lan is to the Fortigate network interface....and the WAN interface goes out via the internet gw on the Public subnet.

However, external site VPNs to those EC2 instances dont work.   (Note: I connect to the EC2 via an AWS vpn which does work)

Packet filters show traffic is routing from the external site policy....across to the AWS fortigate. The AWS packet filter shows the traffic hitting the policy but then tcp retransmissions occur and nothing hits the server.

I thought it might be the default GW on the windows EC2 is not set to the fortigate.  When I set the default GW to the fortigate i lose all access.

Any help would be greatly appreciated.