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Help with getting VDOM-NAT and VDOM-Transparent to share same WAN port?

Hello all, sorry for the post. I have been looking into it for a couple of days and I need a solution ASAP. A client of mine had a firewall onsite that gave out. The device is non functional so I couldn't pull the config settings. I have used Fortigates at several other clients and replaced it with this, but I am having some issues.


Their ISP provides them 4 static public IP addresses on a single DSL line, and at the moment only 2 are being used.

DSL goes into Frontier Modem (Bridged mode) to the WAN 1 of the fortigate.


Public IP:

Subnet: /24



WAN1 on fortigate: 





I need Lan ports 1,2,3 and 5 to go to the Network Devices (Computers etc.) and Lan port 4 to go to a 3rd party Firewall's Wan1 port.


I have set up a VDOM-Root(NAT) and VDOM-3rdParty(Transparent)

I have also set up a vlink from root to 3rdparty using no IP addresses. (


Interfaces on VDOM-Root: Wan1, lan 1, 2, 3 ,4, 5, vlink 0

Interfaces on VDOM-3rd Party: lan 4, vlink1


Third party WAN 1:

Sub: /32



VDOM-Root is functioning properly.

VDOM-3rd Party is not communicating out.


I know I am either missing something or confused how VDOMs are supposed to work. Please let me know if yall can be of any assistance






It looks like you need to create an intervdom link from 3rd party to wan1 root port