Chapter 1 What’s New for FortiOS 5.0 : Other new features : Inter-VDOM links between NAT mode and Transparent mode VDOMs : About inter-VDOM links between NAT and Transparent mode VDOMs
  
About inter-VDOM links between NAT and Transparent mode VDOMs
Inter-VDOM links between NAT and Transparent mode VDOMS can be useful for configurations where the NAT based VDOMs that share a common Internet service route, which can be routed through a Transparent VDOM that provides additional functionality, like common Security inspection, WAN optimization, explicit proxying and so on.
Other examples include:
Performing SSL offloading in the Transparent mode VDOM and providing Internet access through a NAT mode VDOM.
Applying WAN optimization in a Transparent mode VDOM and other security features in the NAT mode VDOM.
Using a dedicated Transparent mode VDOM for the explicit web proxy in front of a NAT mode VDOM that applies other security features.
An ISP configuration with multiple per-tenant NAT mode VDOMs all sharing a single Internet connection but where the ISP only presents a single routed subnet. Each tenant can then be assigned an IP from the subnet for their respective VDOM link interface while using a single physical port to connect to the ISP router.