What session flag indicates that a packet is being bridged in TP mode?

The correct answer is "br," which indicates that a packet is being bridged in transparent mode (TP mode). In this context, "br" stands for bridge, and it signifies that the FortiGate unit is functioning as a layer 2 bridge. This means that the unit is handling packets at the data link layer without performing any routing.

When a packet is processed in this mode, it is not assigned an IP address; instead, it is simply forwarded based on MAC addresses, making the "br" session flag a clear indicator of this bridging behavior. This is particularly useful in scenarios where a transparent deployment is needed, such as when integrating a FortiGate firewall into an existing network without disrupting existing IP addressing or routing architectures.

The other options relate to different functionalities or operational states but do not signify packet bridging in TP mode. The "local" flag typically indicates packets that are destined for the FortiGate unit itself, "wccp" pertains to the Web Cache Communication Protocol, which is used for web caching, and "npu" relates to network processing units handling accelerated packet processing. These flags serve distinct purposes and do not convey the same bridging information as "br."