An engineer configures a PA-440 firewall to act as a switch by creating several Layer...

Basic Concept: Layer 2 interfaces in the same VLAN still depend on zone assignment and intrazone/interzone policy. Same-zone traffic is allowed by intrazone-default unless changed.

Why B is Correct: Placing all three Layer 2 interfaces in the same Layer 2 zone allows same-VLAN communication by default.

Why A is Wrong: Create an Aggregate Ethernet (AE) group that includes all three interfaces. is a valid Palo Alto Networks or networking concept in another context, but it does not implement the exact configuration outcome required by this question.

Why C is Wrong: Create an "allow" Security policy with the source and destination VLAN set to "VLAN 20". is a valid Palo Alto Networks or networking concept in another context, but it does not implement the exact configuration outcome required by this question.

Why D is Wrong: Create a Layer 3 subinterface for VLAN 20 to enable routing. is a valid Palo Alto Networks or networking concept in another context, but it does not implement the exact configuration outcome required by this question.