This article applies to:

• R3000 

Question:

• How should NICs be connected for firewall mode?

Reply:

The general idea behind firewall mode is that traffic will flow into one interface and out the other (and thus the filter is in-line, or pass-through, with the traffic).  As such, the interface that receives traffic from the internal network should be set as the listening interface, and the interface that transmits traffic towards the internet should be set as the block page device.

Notes:

In general, it is best if the two NICs are configured to use different subnets as well.