If you want to use your FortiGate-VM in transparent mode, your VMware server’s virtual switches must operate in promiscuous mode. This permits these interfaces to receive traffic that will pass through the FortiGate unit but was not addressed to the FortiGate unit.
In VMware, promiscuous mode must be explicitly enabled:
- In the vSphere client, select your VMware server in the left pane and then select the Configuration tab in the right pane.
- In Hardware, select Networking.
- Select Properties of vSwitch0.
- In the Properties window left pane, select vSwitch and then select Edit.
- Select the Security tab, set Promiscuous Mode to Accept, then select OK.
- Select Close.
- Repeat steps 3 through 6 for other vSwitches that your transparent mode FortiGate-VM uses.