Virtual inline mode offers two packet-forwarding options:
Return to Ethernet Sender (default)—This mode allows multiple routers to share an appliance. The appliance forwards virtual inline output packets back to where they came from, as indicated by the Ethernet address of the incoming packet. If two routers share a single appliance, each gets its own traffic back, but not the traffic from the other router. This mode also works with a single router.
Send to Gateway (not recommended)—In this mode, virtual inline output packets are forwarded to the default gateway for delivery, even if they are destined for hosts on the local subnet. This option is usually less desirable than the Return to Ethernet Sender option, because it adds an easily forgotten element of complexity to the routing structure.
To specify the packet-forwarding option—On the Configuration: Optimization Rules: Tuning page, next to Virtual Inline, select Return to Ethernet Sender or Send to Gateway.