Palo Alto Networks Certified Network Security Administrator (PCNSA)Initial Configuration and ManagementHard
A network engineer is configuring a Palo Alto Networks firewall in a network segment where the firewall needs to perform both Layer 2 switching and Layer 3 routing functions for different traffic types on the same physical interface. Which interface type allows this mixed functionality?
- ALayer 2
- BTap
- CLayer 3
- DVirtual Wire
Show answer & explanationAnswer & explanation
Correct answer: A. Layer 2
A Layer 2 interface on a Palo Alto Networks firewall can be configured as part of a Layer 2 switch, but it can also have a Layer 3 subinterface (called a VLAN interface) associated with it. This VLAN interface then performs routing functions, allowing the same physical interface to handle both L2 switching and L3 routing for different VLANs.
Why the other options are wrong
- B. Tap interfaces are for passive monitoring and do not forward traffic.
- C. A Layer 3 interface operates solely at Layer 3, forwarding traffic based on IP addresses, and does not perform Layer 2 switching functions.
- D. Virtual Wire interfaces transparently bridge two segments at Layer 2 without IP addresses on the interface itself.
Mixed L2/L3 Interface
A Palo Alto Networks firewall interface configuration that enables both Layer 2 switching and Layer 3 routing on the same physical port, typically using VLANs and VLAN interfaces.
- Achieved with Layer 2 interface and associated VLAN interfaces.
- VLAN interfaces are Layer 3 and assigned to virtual routers.
- Allows flexible deployment in complex network segments.
Memory trick: The L2 interface wears a routing hat for its VLANs.