Two-Armed Deployment - Dell SonicWall SRA 4200 Administrator's Manual

Two-armed Deployment

The SRA appliances also support two-armed deployment scenarios, using one external (DMZ
or WAN side) interface and one internal (LAN) interface. However, two-armed mode introduces
routing issues that need to be considered before deployment. The SRA appliance does not
route packets across interfaces, as there are IP tables rules preventing that, and therefore
cannot be used as a router or default gateway. Any other machines connected to an internal
interface of the SRA appliance in two-armed mode would need to access the Internet or other
network resources (DNS, NTP) through a different gateway.
If you have an internal router as well as an Internet router, you can use a two-armed deployment
to leverage your internal router to access your internal resources.
Sample Scenario - Company A has resources and a number of subnets on their internal
network, and they already have a robust routing system in place. With two-armed deployment
of the SRA appliance, client requests destined for internal resources on the corporate network
can be delivered to an internal router.
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