Fortigate in Azure with VPN concentrator

Hi Team,

We have recently deployed a FortiGate to azure in the hope of creating a nat gateway for our meraki vpn concentrator to provide internet access from a central point for monitoring and compliance.

We have all the internal routing working perfectly and the remote sites can contact the fortigate vice versa through the vpn concentrator.

The vpn concentrator has its default route set to the internal interface of the forigate unit and we can confirm this is correct as the concentrator shows the external IP matches the Fortigate public IP.

We also have static routes on the fortigate that point internal ip ranges such as 10.72.10.4 back via the concentrator on 172.19.2.4

The issue we are facing however is internet traffic will not flow from a remote site, through the concentrator , out the fortigate and back again.

From what i can see the fortigate is doing everything correctly, however it would be awesome if someone could check my flow capture to make sure i have the fortigate configured correctly.

remote win 10 device: 10.72.10.2 sending ping packet to 8.8.4.4

VPN concentrator: 172.19.2.4

FortiGate Outside (port 1): 172.19.0.4 (with public ip)

FortiGate Inside (port 2) : 172.19.1.4

Flow Capture

We are trying to work out if this is a strange azure issue or something else. We have a ticket with Microsoft however they are very slow to assist. I have been told from meraki the vpn concentrator is a simple layer 2 passthrough device and should be sending all traffic to the upstream route.